Data on the size of Indian Rhinoceros, Rhinoceros unicornis, individuals in the wild are only reported in rare cases, usually after the Animal was killed or more recently during translocation exercises. In a survey of literature, records regarding body length, height at shoulder, girth and horn length have been collated and calculated in metric dimensions. The maximum figures are body length to 436 cm, height at shoulder to 206 cm, girth of body to 380 cm and horn length to 61 cm.
Watching a Rhinoceros in its natural habitat while cruising in a tourist jeep, it is impossible to estimate the size of the Animals with any amount of accuracy. It is easier in a zoological garden if the Animals are trained to allow Human interaction, but records of size are rarely if ever published, and it is always possible that their captive diet has some impact on the results.
In the general literature about the rhinoceros there are of course indications of the Animal’s size, either as average or as a range from minimum to maximum. Such figures are meant to give an idea of the bulk of adult animals, in few cases males and females are distinguished. Generally, there is a lack of discussion on how the figures were calculated.
In a survey of literature while working on a history of the Rhinoceros in South Asia, Kees Rookmaaker of the Rhino Resource Center has tried to consistently record the sizes provided by authors who took measurements of Rhinos in the field, usually after the Animal had been killed, which is presented in a paper in the journal Pachyderm. This is unlikely to be an unbiased sample, which would allow calculating some kind of average, because hunters were likely to shoot the biggest and best, or just provide measurements when an exceptional animal had been obtained.
There are definitely pitfalls when using such data by hunters and adventurers. Their methods may have differed considerably, they may not have been particularly knowledgeable about taking measurements, they used a variety of units, and in practice their statements are unverifiable. Rookmaaker has recalculated all figures into metric centimetres, from feet and inches as well as hands.
A comparison of the general statements in the recent literature and the records of the largest Animals killed appeared to show that the upper margins in the size ranges were often too low. Therefore, it is useful to provide all available data. It is not useful to discuss the minimum size of an adult, or average size, because the reports in the literature are really too few to shed any light on that. Similarly, the sexes of the animals are, unexpectedly maybe, rarely recorded, and shed no light on any sexual differences there might be.
In the 19th century, the London taxidermist Rowland Ward set the standards for measuring and recording trophies. Using the Tiger as an example, he recommended that animals were measured in the field between pegs, where pegs are placed are placed by the nose, the nape of the neck, the root of the tail and the tip of the tail. Maximum lengths would therefore include the tail stretched out, adding about 50–60 cm to the total.
The measurements reported by the the pseudonymous BHBAMBT in 1822 of a specimen in Dinagepore (now Dinajpur in northwest Bangladesh) were discarded by Rookmaaker, because the size of the animal appears imaginary, with a length of 482 cm, height of 226 cm, and horn length of 53.3 cm.
Two sets of measurements can be highlighted. Eric Dinerstein provided statistics of Animals examined during translocation exercises in Nepal in 1985-1988, thereby creating a unique set of data based on a larger number of Animals. He separated the data set into calves, sub adults, young adults and older adult males and females. For maximum sizes Rookmaaker has of course only taken the older adults into account. Dinerstein found that males (averaging 411.7 cm in length) were on average slightly larger than females (on average 399.2 cm in length).
The second set is found in the hunting records of Nripendra Narayana Bhupa, the Maharajah of Cooch Behar spanning from 1871 to 1909. In an appendix, Nripendra gave records of 13 of the largest Animals shot in this region of West Bengal. In this table, (the length measured 'between sticks'), the largest specimens are said to be a female in 1890 being 370.8 cm long and 175.6 cm high, and a male in 1895 being 388.6 cm long and 194.6 cm high. However, there are measurements of three large Rhinos shot in Cooch Behar listed by Rowland Ward in 1910, which may agree in height but certainly were said to be longer. Ward probably, lists the large male of 1895 with a similar height of 193.7 cm (against 194.6 cm), but with a greatly larger length of 429.2 cm (against 388.6 cm), which must be explained by differences in the method of measuring.
Kees Rookmaaker has collated the records of the maximum size of wild Rhinoceros unicornis individuals for which exact records have been published over the years for body length, height at shoulder, girth and horn length.
The general size ranges published nowadays often have a maximum of 380 cm or less for total length including tail. The measurements taken in Nepal by Eric Dinerstein gave averages of 399 cm for females, and 411.7 cm for males.
None of the individual records in the literature refer to animals in Nepal. Animals with a length above 4 m are definitely rare. However, 10 such animals have been measured. Rowland Ward, in his work on large trophies, listed three specimens killed in Cooch Behar with record lengths, up to 429 cm. Rookmaaker doesn’t quite understand the difference between the measurements published by the Maharajah of Cooch Behar taken in the field and those reported by Rowland Ward from the trophies, but they possibly do relate to the same specimens.
The largest length recorded is 436 cm. In view of this, it is suggested that the maximum length of the species should be stated as reaching 436 cm.
The study in Nepal by Eric Dinerstein gave a size range for shoulder height of 172.3 cm ± 14.2 in males (4 specimens) and 149.3 cm ± 14.7 in females (3 specimens). Andrew Laurie, Ernst Lang, and Colin Groves gave a range of 163–193 cm (from 9 specimens ), with average 175.4 cm in males. This is only exceeded at the top end by the range of 172–198 cm by Rowland Ward.
There have only been two records for the shoulder height above 2 metres. One Animal from Bihar was measured at just under 206 cm. Surely such heights are exceptional, but a range upto that figure is suggested.
The girth, or circumference of the body, is a rather odd measurement, as it would take some time to find the place on the body where this is the largest. Eric Dinerstein, in his study in Nepal, gave figures of 314.5 cm ± 28.1 in males (4 specimens) and 298.7 cm ± 41.5 in females (3 specimens). Andrew Laurie, Ernst Lang, and Colin Groves gave a figure of 396 cm, which is the highest found in the general recent literature.
The figures provided for wild specimens measured in the field are from 302–381 cm. However, the larger measurement of 396 cm is not inherently impossible and that can be taken as the maximum girth of the species.
he maximum horn length for any Rhinoceros species is a figure often repeated in the literature. The Records of Big Game maintained by Rowland Ward since 1892 are of course authoritative, although the list is not meant to disclose the whereabouts of each specimen. It will be noted that the largest horn obtained in Cooch Behar measured only 41.3 cm, just two-thirds of the larger ones found elsewhere, despite the large size of some of the animals. Horn length is not an indicator of body size.
A very large horn from Assam, said to be 61.5 cm, was recorded by Prabhakar Barua and BN Das in 1969 in the Assam State Museum, Guwahati. When Rookmaaker visited the museum, within the zoo premises, in 2019, the horn was not found. It is likely that it was transferred to the Assam State Treasury, although a recent survey reported in the media in 2016 seems to indicate that the longest in that repository is 46 cm. A search for this extremely long horn is advisable.
Two record horns stand out. For a long time, the horn of 54.0 cm obtained by the Viceroy of India, George Curzon, 1st Marquess Curzon of Kedleston (1859–1925) in eastern Nepal in 1901 was cited as the best specimen. It was illustrated by Rowland Ward, and is still known to exist.
A horn of 61.0 cm (in dry state) or 61.6 cm (in the field) was obtained by Thomas Charles Briscoe (1857–1909) in Assam in 1909. This record horn is preserved in the Natural History Museum, London specimen (no. ZD.1910.1.23.1); and was often illustrated in the press.
The data published for the extremely large specimens of Rhinoceros unicornis in the wild don’t provide information on sexual dimorphism, as the sex of the Animals was rarely recorded. In Cooch Behar, the largest male exceeded the largest female in dimensions, but this is not necessarily a general characteristic. Measurements of zoo Animals may not be representative for a wild population due to changes of feeding.
This study was not concerned with minimum measurements. Taking those from the general literature, the following ranges for measurements can be suggested: Length of body, 300–436 cm; Height at shoulder, 140–206 cm; Girth, 250–380 cm; Horn, up to 61 cm.
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