Four fishermen killed by Hippopotamuses by Lake Naivasha, Kenya.

Four members of a group of ten fishermen have been killed after being attacked by Hippopotamuses by Lake Naivasha in Kenya on Friday 2 January 2025. The group, who have been described as local youths, approached the lake after dark as they lacked fishing permits, and are thought to have disturbed a group of Hippos with calves. Six of the party were able to escape by entering the water and swimming, or by climbing trees. One of the deceased is described as having initially escaped, but to have returned in an attempt to rescue a friend. 

Hippopotamuses by Lake Naivasha, Kenya. The Sunday Standard.

Lake Naivasha is noted for undergoing marked variations in its depth, and therefore extent. Water levels in the lake dropped continuously during the first half of the twentieth century, falling to 60 cm in 1945, then rose steadily for over two decades, reaching 6 m in 1968. The waters then fell until 1987, when the lake was only 2.25 m deep, but have been trending upwards since this time, causing the land to expand, swamping low lying villages and farmland, something which has accelerated in recent years as warming global temperatures have led to increased rainfall in East Africa.

One upshot of this that the lake naturally contains no commercially harvestable fish, probably as a result of drying up on occasions in the past. Non-native fish have been introduced to the lake in order to create a commercial fishery, but this has proven difficult to manage, with a dramatic fish-population crash fuelled by overfishing in 2001 leading to the introduction of strict fishing regulations on the lake.

This has created in a fish stock available to commercial fishing companies, and foreign tourists, but not to local villagers, resulting in frequent attempts to circumnavigate the regulations, for example by fishing at night. This has become more of a problem as the lake has expanded, swallowing up farmland and leaving the local population looking for other sources of sustenance. The expansion of the commercial flower growing industry, which earns the nation hard currency but also takes up farmland in the Rift Valley around lakes such as Naivasha and employs a relatively low number of people, has also tended to push people towards illicit economic activities such as night fishing, as well as fuelling conflict between Humans and aquatic wildlife such as Hippopotamuses and Crocodiles.

Flooding in a community beside Lake Naivasha in November 2025. Tony Karumba/AFP.

While Hippos can appear benign to people unfamiliar to them, they are generally considered to be one of the most dangerous Animals in Africa, and probably the world. Hippopotamuses are the largest land Mammals after Elephants and Rhinoceroses, as well as being the closest terrestrial relatives of Whales. Adult Hippos typically weigh about 1.4 tonnes (males tend to be slightly larger than females, but this is marginal, and the sex of Hippos can be hard to differentiate). Hippos can open their mouths to almost 110°, and their jaws are highly muscled, allowing them to slap there mouths shut abruptly, driving canine and incisor teeth that can be 50 cm long into anything which offends them. This weapon is primarily used in intraspecific fights particularly between the males, which are highly territorial. However, they are also notoriously aggressive towards other species, particularly Humans, possibly as a result as having evolved alongside Pliocene and Pleistocene hunting Hominids. Hippopotamuses tend to stay in the water during the day, lowering the threat they present to Humans, but come out of the water to graze at night, when they are generally considered to be at their most dangerous.

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Magnitude 6.5 Earthquake in Guerrero State, Mexico.

The United States Geological Survey recorded a Magnitude 6.5 Earthquake at a depth of 35.0 km, approximately 4 km to the north of the resort of Rancho Viejo in Guerrero State, slightly before 10.00 am local time (slightly before 2.00 pm GMT) on Friday 2 January 2025. This even was felt across much of southern and central Mexico, with at least two people having died, a 50-year-old woman in Guerrero State, and a 60-year-old man in Mexico City. At least 12 further people were injured by the event. 

The approximate location of the 3 January 2026 Guerrero State Earthquake. Contour lines show rates of movement during the quake, the red line is the Middle American Trench. USGS.

Mexico is located on the southernmost part of the North American Plate. To the south, along the Middle American Trench, which lies off the southern coast off Mexico, the Cocos Plate is being subducted under the North American Plate, passing under southern Mexico as it sinks into the Earth. Guatemala is located on the southern part of the Caribbean Plate, close to its boundary with the Cocos Plate, which underlies part of the east Pacific. The Cocos Plate is being pushed northwards by expansion of the crust along the East Pacific Rise, and is subducted beneath the Caribbean Plate along the Middle American Trench. This is not a smooth process, and the plates frequently stick together then break apart as the pressure builds up, causing Earthquakes in the process. 

The position of the Cocos, Nazca and Rivera Plates. MCEER/University at Buffalo.

The Cocos Plate is thought to have formed about 23 million years ago, when the Farallon Plate, an ancient tectonic plate underlying the East Pacific, split in two, forming the Cocos Plate to the north and the Nazca Plate to the south. Then, roughly 10 million years ago, the northwesternmost part of the Cocos Plate split of to form the Rivera Plate, south of Beja California.

In a paper published in the Journal of Geophysical Research, in 2012, a team led by Igor Stubailo of the Department of Earth and Space Sciences at the University of California Los Angeles, published a model of the subduction zone beneath Mexico using data from seismic monitoring stations belonging to the Mesoamerican Seismic Experiment, the Network of Autonomously Recording Seismographs, the USArray, Mapping the Rivera Subduction Zone, and the Mexican Servicio Sismologico Nacional.

The seismic monitoring stations were able to monitor not just Earthquakes in Mexico, but also Earthquakes in other parts of the world, monitoring the rate at which compression waves from these quakes moved through the rocks beneath Mexico, and how the structure of the rocks altered the movement of these waves.

Based upon the results from these monitoring stations, Stubailo et al. came to the conclusion that the Cocos Plate was split into two beneath Mexico, and that the two plates are subducting at different angles, one steep and one shallow. Since the rate at which a plate melts reflects its depth within the Earth, the steeper angled plate melts much closer to the subduction zone than the shallower angled plate, splitting the Trans-Mexican Volcanic Belt into sections above the different segments of the Cocos Plate, and causing it to apparently curve away from the subduction zone.

Top the model of the Cocos Plate beneath Mexico, split into two sections (A & B) subducting at differing angles. (C) Represents the Rivera Plate, subducting at a steeper angle than either section of the Cocos Plate. The Split between the two has been named the Orozco Fracture Zone (OFZ) which is shown extended across the Cocos Plate; in theory this might in future split the Cocos Plate into two segments (though not on any human timescale). Bottom Left, the position of the segments on a map of Mexico. Darker area is the Trans-Mexican Volcanic Belt, orange circles are volcanoes, brown triangles are seismic monitoring stations, yellow stars are major cities. Bottom Right, an alternative model showing the subducting plate twisted but not split. This did not fit the data. Stubailo et al. (2012).

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The Quadrantid Meteor Shower.

The Quadrantid Meteor Shower is one of the brightest meteor showers of the year, often producing over 100 meteors per hour at its peak, which falls around 3-4 January each year, and is predicted to peak at about 11.00 pm on Saturday 3 January 2026. Unfortunately, this coincides with the Full Moon this year, which may hamper viewing somewhat.

The meteor shower originates in the constellation of Boötes, high in the northern sky, which is slightly confusing, as most meteor showers are named for the constellation in which they originate. This is because the constellation was named in the sixteenth century by astronomer Tycho Brahe, before the introduction of standardised constellations used by modern astronomers, though to make matters a little more confusing, Brahe didn't name the meteors this way either; the name comes from the constellation of Quadrans Muralis, introduced by Joseph Jérôme Lefrançois de Lalande in 1795, and dropped by the International Astronomical Union in 1922. Because Boötes is visible only from the Northern Hemisphere, the Quadrantid Meteor Shower is not visible from the Southern Hemisphere, and is best viewed from northerly locations such as Canada or Scandinavia.

The radiant point of the Quadrantid Meteors (i.e. the point from which the meteors seem to radiate). American Meteor Society.

Meteor streams are thought to come from dust shed by comets as they come close to the Sun and their icy surfaces begin to evaporate away. Although the dust is separated from the comet, it continues to orbit the Sun on roughly the same orbital path, creating a visible meteor shower when the Earth crosses that path, and flecks of dust burn in the upper atmosphere, due to friction with the atmosphere.

The Earth passing through a stream of comet dust, resulting in a meteor shower. Not to scale. Astro Bob.

The Quadrantid Meteors are unusual in that they typically are only visible for a few hours either side of this peak, whereas other showers are typically visible for days or even weeks. This is thought to be because they originate from an asteroid (196256) 2003 EH1, rather than the tail of a comet as with most meteor showers. The orbit of this asteroid is tilted at an angle of 71.9° to the plane of the Solar System, so that the Earth only very briefly passes through the debris trail left by it, rather than remaining in it for some time, as is the case with the trail of a comet with an orbit in roughly the same plane as the Earth.

The calculated orbits and position (196256) 2003 EH1 and the planets of the Inner Solar System at 11.00 pm GMT on Saturday 3 January 2026.  JPL Small Body Database. 

(196256) 2003 EH1 is a 2.6-4.0 km diameter object with a 2017 day (5.52 year) orbital period, with an elliptical orbit tilted at an angle of 70.8° to the plain of the Solar System which takes in to 1.19  AU from the Sun (119% of the distance at which the Earth orbits the Sun) and out to 5.05 AU (505% of the distance at which the Earth orbits the Sun slightly inside the orbit of the planet Jupiter). This means that close encounters between the asteroid and Earth happen occasionally, with the last calculated to have happened in December 1936 next predicted in December 2052.  It is therefore classed as an Amor Group Asteroid (an asteroid which comes close to the Earth, but which is never closer to the Sun than the Earth is). (196256) 2003 EH1 also has occasional close encounters with the planet Jupiter, with the last having happened in June 1984, and the next predicted for March 2044.

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The distribution and conservation status of Wild Rooibos Plants, Aspalathus linearis.

Rooibos Tea is a traditional herbal drink from South Africa, not marketed internationally. It is made from the leaves of the Rooibos Plant, Aspalathus  linearis, a type of Cape Gorse which grows wild in dry areas of the northwestern part of the Fynbos Biome, part of the wider Cape Floristic Region. Although traditionally harvested from wild plants, the modern Rooibos industry is built around large scale cultivation of the plant, with only a tiny amount of the total crop harvested from the wild.

Thus the Rooibos Plant is considered to be an economically significant plant in South Africa. Although the commercial harvest is tied to agricultural production, this the wild population preserves a  wider genetic heritage, which may become important should the commercial crop be threatened by disease or climate change. However, while quite a lot of research has been published into Rooibos, most of this relates to commercial cultivation, leaving us with little understanding of the ecology, distribution, or conservation status of the wild plants.

In a paper published in the South African Journal of Science on 26 November 2025, Tineke Kraaij of the Natural Resource Science and Management Cluster at Nelson Mandela University, Vernon Visser of the Centre for Statistics in Ecology, Environment and Conservation, and National Institute for Theoretical and Computational Sciences, at the University of Cape Town, and Gerhard Pretorius of NaturaLibra Environmental Services, present the results of a study which looked at the current distribution, potential distribution, population size, and threats to the population size of Wild Rooibos Plants in South Africa, with a view to creating a baseline against which future monitoring of the species could be measured.

Rooiboss is grows in areas with cold wet winters and hot dry summers, with annual rainfall levels of between 300 and 600 mm, and at elevations of between 450 and 900 m. It is found as far north as Vanrhynsdorp and as far south as Betty's Bay and the Cape Peninsula, and anecdotally grows as far east as Riviersonderend and Bredasdorp, 

Wild Rooibos is an extremely variable species (potentially being a species cluster - a group of closely related species difficult to tell apart - rather than a true species), and can be difficult to differentiate from closely related African Gorse species such as Golden Tea, Aspalathus pendula, or Lebeck's Roiibos, Aspalathus lebeckioides. Wild Rooibos also has several different ecotypes, strains of the plant with different morphologies and environmental preferences, further complicating efforts to understand the distribution of the species.

The ecotypes of Wild Rooibos vary in habit, fire-survival strategy, vegetative and reproductive morphology, biochemistry, and genetics. They can be loosely grouped into four main forms, 'Erect' or 'Upright', 'Prostrate', 'Bush' or 'Shrub', and 'Tree' (although 'Tree' is sometimes regarded as a variant on the 'Erect' or 'Upright' form). A 'Salignus' form is also sometimes recognised, this having a Willow-like growth with multiple lanky stems reaching 2-3 m tall and a sparse canopy. The Prostrate and Shrub forms are wider than they are tall, and tend to have many branches close to the ground, and can resprout after a fire. The Erect, Tree, and Saliginus forms are tall, and only regrow from seeds. In addition to these, there is the commercially grown 'Nortier' form, a cultivar bred from the Erect form, which is tall like its parent, but also has the dense branching of the Bush form, giving it a large harvestable biomass. 

Exemplary images of the different ecotypes or growth forms of Wild Rooibos, Aspalathus linearis, namely the (a) Bush or Shrub form, (b) Prostrate form, (c) Erect (including Upright or Tree) form, and (d) Salignus form. Kraaij et al. (2025).

These different ecotypes have different distributions. The Bush, Prostrate and Tree types occur towards the northern part of the species’ range, and the Prostrate, Erect and Salignus types toward the south. The Erect and Salignus types favour higher elevations, above 400-600 m. The Bush ecotype is predominant in areas with low rainfall (less than 200 mm per year), while the Salignus ecotype favours wetter areas (more than 500 mm per year), and lower elevations. Different ecotypes often coexist in the same region, but seldom close to one-another. 

Kraaij et al. built up a map of the distribution of Wild Rooibos and its various ecotypes, using data from the Global Biodiversity Information Facility and CapeNature databases, previously published research, and fieldwork carried out by Gerhard Pretorius. As much as possible, sites with historic records of the plants were visited to establish their continuing presence (or absence). Additional observations were made along roads connecting historic observation sites.

This data was then used to build a model of the potential distribution of the species, and the Bush, Prostrate, Erect, and Saligus ecotypes. This was achieved by mapping the presence of the plants against a range of variables, including precipitation in the  warmest quarter; precipitation in the coldest quarter; maximum temperature of the warmest month; minimum temperature of the coldest month; topographical slope; soil electrical conductivity; soil potassium, sodium, phosphorus, carbon, and nitrogen levels, soil pH; and the proportion of sand in the soil. 

Of the 235 sites where the species was historically recorded, it was found to now be absent from 30, and present at 47. In addition, 99 new locations where the species was present were identified. The species was not found at an outlier north of Nieuwoudtville and one east of Vanrhynsdorp, and some locations around Citrusdal, not was it found south of Malmesbury, at Franschoek, on the Cape Peninsula, or in the Gordon’s Bay and Betty’s Bay areas. It was confirmed at De Doorns, the easternmost location where it was previously recorded. Kraaij et al. note that the absence of the species at a site where it was historically recorded does not imply local extinction; it is possible that the previous records were miss-identifications. Notably, the habitat at some of these locations appeared completely unsuitable for Rooibos, with very steep slopes, clay soils, or wetlands, and a plant assemblage different from that associated with Rooibos plants. Some records of the plant in southern areas listed on iNaturalist could be verified, suggesting that it is not absent from the claimed southern extent of its range, but the species mainly occurs in the area between Nieuwoudtville in the north, Groot Winterhoek in the south, Wupperthal and the Tra-Tra mountains in the east, and just southeast of Graafwater in the west.

Results of field verification of historical location records of Wild Rooibos, showing where Rooibos was present, absent or not verified, as well as new location records. Kraaij et al. (2025).

The Wild Rooibos population was predicted to extend from Nieuwoudtville in the north to just southeast of Ceres, with the bulk of its distribution around Clanwilliam and Citrusdal, which was largely in line with predictions based upon previous reports. In total the species occupied an area of about 6000 km², with individual ecotypes occupying areas of between 1500 and 2500 km². The Salignus ectotype was the most abundant, predicted to occupy an area of about 254 600 km², followed by the Prostrate ecotype, 161 200 km², the Bush ecotype, 121 100 km², and the Erect ecotype, 119 900 km². Because each ecotype and the species as a whole were modelled separately, the species total does equal the total for each ecotype minus the overlap between different ecotypes. 

Overlap between ecotypes was only substantial in the core area of the distribution range. The Bush and Prostrate ecotypes had roughly similar distributions, extending east and south of the core area. The Erect and Salignus ecotypes had distributions extending west and north of the core area, with the Salignus ecotype predicted to extend furthest west, beyond Piketberg. The Salignus ecotype was also predicted to be found in the south, around Ceres. 

The distribution of the different ecotypes appeared to be driven by different factors. The distribution of the Bush and Prostrate ecotypes appeared to be influenced by the coldest cool period temperature, with both ecotypes able to cope with sub-zero temperatures. Warm season precipitation was clearly important to these ecotypes as well, with both favouring low summer precipitation. The distribution of the Erect and Salignus ecotypes was most strongly influenced by the concentration of potassium in the soil, with both ecotypes favouring very low concentrations. The Erect ecotype also appeared to need low soil conductivity. The distribution of both Erect and Prostrate Ecotypes was also influenced by the concentration of carbon in the soil with both ecotypes favouring very low levels. Kraaij et al. note that high winter temperatures and wet summers favour the growth of pathogenic Oomycetes such as Pythium spp. and Phytophthora cinnamomi, which are known pests of farmed Rooibos.

Kraaij et al. also produce estimated population sizes for the species and each ecotype. They again note that the total for the species does not match the total for each ecotype added together, as these were calculated separately. Three estimates for each population were made, based upon the minimum, mean, and maximum density of the plants. For the species as a whole, the minimum population was estimated at 14.7 million plants, while the mean was 1.78 billion plants, and the maximum was 17.0 billion plants. The most abundant ecotype, Salignus, was estimated to have a minimum population of 144 million plants, a mean population of 390 million plants, and a maximum population of 630 million plants. For the Prostrate ecotype the figures were, minimum 4.35 million plants, mean 863 million plants, and maximum 4.66 million plants. For the Bush ecotype the figures were minimum 13.3 million plants, mean 325 million plants, and maximum 1.34 billion plants. Finally, for the Erect ecotype, the figures were minimum 3.00 million, mean 189 million, and maximum 833 million plants.

Kraaij et al. recommend, however, that these figures be taken with a good deal of caution, as characterising the species distribution and abundance in the landscape was challenging in many cases, with significant implications for the population estimates. The density of Prostrate plants was particularly hard to estimate, particularly when it was interspersed with other plants. The species has a highly irregular distribution across its range, with plants often forming dense clumps in the midst of apparently similar and equally habitable, but unoccupied, landscapes. Both the size and density of individual populations varied a great deal from site to site. Furthermore, most populations were detected from a moving vehicle, requiring a minimum density for observation; it is possible that less dense populations were overlooked. Finally, Rooibos plants grow in a landscape prone to periodic burning. This does not appear to damage the population as a whole, but the plants do take time to recover after a fire, so their presence is likely to have been missed in areas which had recently burned.

Given these constraints, Kraaij et al. estimate that the populations of the species and each ecotype are probably towards the lower ends of their estimated numbers, but that more detailed surveys of each population would be needed to confirm this.

Much of the population of Wold Rooibos appears to be on protected land. Kraaij estimate that 27% of the total population is found on state or private protected areas, with 38% of the Prostrate ecotype, 33% of the Salignus ecotype, 28% of the Bush ecotype, and 20% of the Erect ecotype occurring on protected land.

About 40% of the Wild Rooiboss population was found to be growing in areas where Kraaij et al. considered that it faced no threats. Another 13% was found in areas where it was prone to illegal harvesting, although this was not thought to present a major threat to the species. About 28% of the population was growing in areas where land transformation presented a threat, although much of this land was probably unsuitable for conservation, and was likely to receive some protection from legislation preventing the clearing of natural vegetation. About 4% of the land where the species grew is potentially threatened by overgrazing, although this does not appear to present a direct threat to Wild Rooibos plants. About 15% of the sites were threatened by invasive plants, particularly Dodder, Cuscuta campestris, a parasitic climbing plant from North America, which can target a wide range of hosts and which is a problematic invasive species in several parts of the world. Cultivated Rooibos fields are known to be prone to invasion by Golden Wreath Wattle, Acacia saligna, and Cyclops Wattle, Acacia cyclops, but while these are a problem in Rooibos fields, they do not seem to be a problem in the natural setting. Potentially, climate change could alter the fire regime in the areas where Wild Rooibos grows. However, the species currently grows in areas where fires are fairly infrequent, with the interval between fires typically significantly longer than the regrowth of the plants, so any shift in fire regime would have to be significant to cause a problem.

Climate change could also potentially alter rainfall patterns and temperature in areas where Wild Rooiboss grows. Since these are variables known to affect the distribution of the plants, this could potentially have a major impact on the species, particularly if winters become warmer and wetter. Two of the populations visited during the study appeared to have suffered widespread mortality events following high summer rainfall events in the summer before being visited. Cultivated Rooibos is also known to be intolerant of waterlogged soils, requiring farmers to implement careful drainage schemes. Since a wetter climate is a predicted outcome of a warming climate in the Western Cape, this could be a major threat to the future of the species. 

Wild Rooiboss does not appear to be at risk from hybridisation. The various ecotypes do not appear to interbreed, even when in close proximity to one-another. Potentially each ecotype could be threatened by inbreeding depression if populations become isolated. As it stands, geneflow within the species is not really understood, though it is likely that geographical barriers such as wide rivers and mountain ranges present a barrier to pollination, and the main distributors of the seeds of the plants are Ants, which do not tend to move long distances. Despite the variety of ecotypes, Wild Rooiboss does not show a great deal of genetic diversity as a species, with even less diversity in the southern part of its range. This lack of diversity could potentially present a threat to the species, and should be considered carefully during any conservation efforts. 

There are more than 9000 fields of Cultivated Rooiboss in South Africa, with 4181 occurring within the natural range of the species as calculated by Kraaij et al. Of the 146 Wild Rooibos populations varified, 55 were found to be within 1 km of Cultivated Rooibos fields. Theoretically, hybridisation between Wild and Cultivated Rooibos is possible, but this was not observed, Cultivated Rooibos plants do not persist well after cultivation ceases, which, combined with the apparently limited gene flow between ecotypes, suggests that hybridisation with the Cultivated form does not present a major threat to Wild Rooiboss populations. 

Wild Rooibos has a limited and fragmented distribution, but within this range appears to be common. The total wild population of the species is estimated to be more than 15 million plants. About 27% of the species distribution lies within protected areas. The species does not appear to be threatened by illegal overharvesting, invasive plants, overgrazing, or fire regimes, nor by hybridisation with the Cultivated form. The potential for habitat transformation appears to present only a minor threat to the species. By far the greatest threat to Wild Rooibos appears to be the potential effects of global warming, potentially bringing warmer, wetter conditions unfavourable to the species. This could well cause the range inhabited by the species to contract, with little potential for migration to better climates without Human intervention. 

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Using Environmental DNA to search for Crocodiles in Madagascar.

The world is currently suffering from multiple interconnected environmental crises, including a rapid loss of biodiversity in many parts of the world. Madagascar, a global biodiversity hotspot with a large number of species found nowhere else, is considered to be particularly at risk, due to unprecedented rates of habitat loss. However, tracking this loss is challenging, as monitoring species loss involves a large amount of labour intensive work by specialist taxonomic experts, often involving access to expensive equipment.

Environmental DNA offers a potential way to reduce this workload, allowing for monitoring to be carried out by non-specialist staff collecting samples of sediment, water or even air. Since such methods to not require direct observation of threatened species, they are far less environmentally intrusive.

Nile Crocodiles, Crocodylus niloticus, were persecuted across their range by hunters seeking their skins, as well as harvesting of their eggs, until the mid-twentieth century. Since this time, the population has recovered in many parts of Africa due to conservation efforts. In Madagascar, the species is monitored by the Malagasy Crocodile Management Unit, which aims not just to establish the recovery of the species, but to minimise Human-Crocodile conflicts by helping people and livestock to avoid potentially lethal Crocodile encounters.

Previous work using environmental DNA has succeeded in detecting Crocodiles kept under laboratory conditions, but struggled to locate them in the wild, although methods such as water sweeps have proven more successful.

In a paper published in the journal Biodiversity and Conservation on 23 October 2025, Mai Fahmy of the Department of Undergraduate Biololgy at Stony Brook University, and the Division of Invertebrate Zoology at the American Museum of Natural History, Soja Manjakamanana Zafimanaoela of the Université d’Antananarivo, Njakamamapiadana Mamenofahasoavana Rinah and Jerison William Ranaivosolo of Stony Brook University's Centre ValBio in Madagascar, Noel Rowe of Primate Conservation Inc., Patricia Wright, also of the Centre ValBio, and of the Department of Anthropology and Interdepartmental Doctoral Program in Anthropological Sciences at Stony Brook University, and Evon Hekkala, also of the Department of Undergraduate Biololgy at Stony Brook University, and the Division of Vertebrate Zoology at the American Museum of Natural History, present the results of a study, in which they attempted to detect Crocodiles in Madagascar using sediment samples as well as specialist environmental DNA filters and Coffee filters, in an attempt to find a cost-effective method of detecting the Animals. 

Anivorano lake in northern Madagascar, traditionally held to be sacred. Here the local population periodically sacrifices Zebu Cattle to the Crocodiles, which are believed to contain the spirits of pas chiefs, in a ceremony that also involves dancing and singing. On such occasions, the Crocodiles are fed beef from a beach about 30 m long near a sacred tree, and subsequently typically remain in the area for about eight hours, basking on the beach or in the water.

Map of collection localities across Madagascar. TSP, Tsimanampetsotse National Park. Fahmy et al. (2025).

Fahmy et al. collected sediment from a belly print left on the beach by a Crocodile, Crocodile faecal matter, and water from an area close to where Crocodiles were basking. The water and faecal samples were subsequently passed through Coffee filters, which were retained. 

At the Ankarana Special Reserve, also in northern Madagascar, Fahmy et al. collected sediment samples from the river mouth leading into the Ankarana Cave System, with two samples collected from the footprints of Crocodiles, one adult and one juvenile. Water was also collected from a flooded cave entrance, and again filtered through a coffee filter.

Water samples were also collected from the Ihosy, Mananantanana, and Matitanana rivers in central and southeastern Madagascar, and filtered through specialist environmental DNA filters. These are wide, fast flowing rivers, used exclusively by the local population for transport, hygiene, and watering livestock. Samples were taken following sightings of Crocodiles, and only with the explicit permission of local communities.

Nile Crocodile, Crocodylus niloticus, spotted in the Matitanana River while sampling. Mai Fahmy in Fahmy et al. (2025).

Finally, four samples were collected from a submerged cave located in Tsimanampesotse National Park in southwest Madagascar. Nile Crocodiles have never been observed in these caves, although they are known to inhabit the nearby Onalahy River. The caves were, however, utilised by the extinct Madagascan Horned Crocodile, Voay robustus, which is thought to have died out about 1250 years ago. These samples were again filtered through Coffee filters. A sediment sample was also collected from beneath a subfossil Horned Crocodile in the caves.

A total of seventeen samples were collected and processed. Four of the samples were subsequently discarded because they were found to contain only Human DNA, and one because it contained Sheep DNA. In the remaining samples, the greatest number of species were recovered from the Coffee filter samples; although this did not represent the greatest diversity. Sediment and environmental DNA samples produced equal numbers of species, although greater overall diversity was recorded in the sediment samples. DNA associated with members of the Family Podicipedidae (Grebes) was recovered exclusively in the environmental DNA filters, while DNA associates with the Family Naididae (Tubifex Worms) was recovered exclusively from sediment samples.

Crocodile DNA was recovered from both sediment samples and Coffee filters, but not from specialist environmental DNA filters. However, Fahmy et al. do not suggest that this is because Coffee filters are superior to environmental DNA filters, as the later were only used to filter water samples from fast flowing rivers, where recovering Crocodile DNA is known to be difficult. 

Zebu Cattle drinking from Matitanana River. Mia Fahmy in Fahmy et al. (2025).

Three samples yielded Crocodile DNA, all from Lake Anivorano. These included the sediment sample taken from the Crocodile belly print, and the Coffee filters through which the faecal sample and water from close to Crocodiles basking in the lake were filtered. The analysis recovered these as belonging to the genus Crocodylus, and most likely as coming from Nile Crocodiles, Crocodylus niloticus, with a lower chance of coming from Orinoco Crocodiles, Crocodylus intermedius, of American Crocodiles, Crocodylus acutus, neither of which are found in Madagascar. 

The three most abundant species in the results were Cattle, Bos taurus, Chickens, Gallus gallus, and Domestic Pigs, Sus scrofa. Also detected were Ring-tailed Lemur, Lemur catta, and an unknown species of Grebe (Podicepepidae). This could not be identified to species level, although several Grebes are known from Madagascar, including the Little Grebe, Tachybaptus ruficollis, and the Madagascar Grebe, Tachybaptus pelzelnii. Interestingly, the Madagascar Grebe does not have any genetic material recorded in the GenBank database, against which the samples were compared.

The method developed by Fahmy et al. did not establish the presence of Crocodiles in anywhere they were not known to occur, but did establish that it was possible to detect Crocodiles using environmental DNA in Madagascar, and that it was possible to use Coffee filters as a means of recovering environmental DNA, a much cheaper option than specialist filters.

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