Happy World Tapir Day!
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| Image 1.1 - Tapir-themed jungle cake |
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| Image 1.2 - Quick world tapir card to celebrate the occasion. © X O'Reilly |
Tapirs are bulky, forest herbivores, feeding on soft vegetation and fruits. They are mainly active after dark and are usually solitary, unless with a single youngster. In bountiful territories, tapir densities can reach 0.8 individuals per square kilometre. Throughout parts of their range, tapirs are hunted for their meat; however, the real threat to their survival in our human-infested world is habitat encroachment.
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| Image 2 – Left: Central American tapir (Tapirus bairdii), from travelcostarica.nu/mammals, © Imágenes Tropicales. Right: Lowland tapir (Tapirus terrestris), from ARKive.org, © Bruce Davidson |
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| Image 3 – Moeritherium, an early form of elephant. © Luci Betti-Nash, Stony Brook University |
Now, you may think tapirs (Image 2) look a little like the result of the ungodly matrimony of a pig and a hippo, or perhaps some form of elephant (Image 3). However, they are part of the order Perissodactyla, the odd-toed ungulates, along with horses and rhinos.
There are four species of tapir (see appendix 1): one, Tapirus indicus, native to Southwest Asia; and three, T. terrestris, T. bairdii, and T. pinchaque, from Central and South America. This is what I find most interesting about tapirs, their peculiar geographic distribution. The existence of a single Asian species makes tapirs more commonly known as South American animals. But how did tapirs get from South America to Asia?
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| Image 4 - Extant tapir distribution. Image © IUCN Tapir Specialist Group, http://www.tapirs.org/tapirs/tapir-range-maps/all_sp-poster_large.jpg |
Perissodactylans really radiated during the Eocene, about 55 million years ago (mya). Tapirs were no exception, and by the late Eocene, the modern genus that all extant tapirs belong to had appeared. Since then, tapirs have not changed all that much. One notably primitive feature is the retention of the fourth digit on their front feet.
Once upon a time, the Earth's landmass was all bundled together as the supercontinent Pangea, which, during the time of the dinosaurs, split into Laurasia (the modern landmasses of North America and Eurasia) and Gondwana (South America, Antarctica, Africa, Madagascar, India, and Australia). By the Eocene, when tapirs evolved, the South American landmass had long since split away from its African and Antarctic partners. So the thought of tapirs crossing from South America into Asia is implausible.
However, if one were to look into the provenance of fossil record, they'd notice that those primitive tapirs were not found on the South American continent at all. They were northern animals, found in the North American and Eurasian landmasses, which were still held together at that time. The real question is, how did they get to South America?
It looks like tapirs – along with many other charismatic Latinamerican mammals, such as jaguars and other felids, as well as llamas and alpacas, relations of the camel – headed south through North America during the Great American Interchange, about 3 mya. This is when the Americas finally joined up.
The rest is history – tapirs went extinct throughout most of their home range after that, leaving no living proof of their existence in North America or Europe and just one lonely species in Southeast Asia.
That is about as much as I know about tapirs. Apart from the relationship between a coati and a tapir that Overall (1980) reported, where the coati would rid the ungulate of all manner of bloodsucking parasites. I just thought that was cute.
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| Image 5 – Tapir track in Payamino. © X O'Reilly |
In a couple of weeks I will be attending the 1st Latinamerican Tapir Conference and the 2nd Ecuadorian Mammalogy Conference in Puyo, Ecuador – I expect these to be insightful into the world of the tapir and its other mammalian countrymen. I'm also hoping that some tapirs will have the decency to show their peculiar proboscis in front of some of my camera traps! Thus far, the cameras have captured deer, ocelots, birds previously unrecorded in this area, a giant anteater, and even a jaguar – but no tapir! Yet I have encountered their tracks on more than one occasion (Image 5). They seem to be mocking me.
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Consulted literature:
Eisenberg, J. F. and Redford, K. H. (1999). Order Perissodactyla (Odd-toed ungulates). In Mammals of the Neotropics: the Central Neotropics (Ecuador, Peru, Bolivia, Brazil). University of Chicago Press, Chicago. Volume 3: 327—331.
Eisenberg, J. F. and Thorington, R. W. Jr (1973). A preliminary analysis of Neotropical mammal fauna. Biotropica 5: 150—161.
Overall, K. L. (1980). Coatis, tapirs, and ticks: A case of mammalian interspecific grooming. Biotropica 12: 158.
Consulted blogs / web pages:
"Family Tapiridae: Tapirs" by Brent Huffman on Ultimate Ungulates. May 8, 2010. www.ultimateungulate.com/Perissodactyla/Tapiridae.html
"Wandering Tapirs" by Brian Switek on Laelaps. 9th March 2008. www.scienceblogs.com/laelaps/2008/03/11/wandering-tapirs/
"The Geography of Tapirs" by Greg Mayer on Why Evolution Is True. 6th August 2009. https://whyevolutionistrue.wordpress.com/2009/08/06/the-geography-of-tapirs/
Tapir Specialist Group, http://www.tapirs.org
Appendix 1: Extant tapir species, © Tapir Specialist Group.
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| Appendix 1 – Extant tapir species. © IUCN Tapir Specialist Group |
Good topic.
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