Toxodon

***Toxodon*** (name meaning "*Bow Tooth*") is a genus of Notoungulata that originated during the Late Miocene epoch in what is now South America. A large hippo-like mammal measuring 4 meters long and weighing 2 tons, it was probably the most common large-hoofed mammal in South America at the time of its existence.

In the Series 3 episode "***Saving the Sabre Tooth***," a herd of a dozen *Toxodon* and their babies were brought to the park from Early Pleistocene South America, 1 million years ago. They reside in the Giraffe Grasslands Enclosure.

## Facts

### Era & Discovery

*Toxodon* lived in South America during the Late Miocene to the Middle Holocene epochs, over 11 million to 5,000 years ago. They were among the largest herbivores of their time, and as such, were prey items along with *Macrauchenia* for animals like *Smilodon and Phorusrhacos*. *Toxodon* became extinct at the end of the Pleistocene when North America and South America met and a migration of more competitive herbivores came about, as well as predators.

   In 1837, Charles Darwin was one of the first to collect *Toxodon* fossils, after paying 18 pence for a *T. platensis* skull from a farmer in Uruguay. Many *Toxodon* remains have been found in close proximity to primitive arrowheads, a sure sign that this slow, lumbering beast was hunted to extinction by early humans.

### Physical Attributes

*Toxodon* was a large hippo-like creature that stood more than 6 feet (2 m) tall, measured 10 – 14 feet (3 – 4 m) long, and weighed about 1.5 – 2 tons (3,000 – 4,000 lbs.), making them among the largest animals in South America during their time.

*Toxodon* is what paleontologists call a "*notoungulate*", a megafauna mammal closely related to the ungulates (hoofed mammals) but is not quite in the same ballpark. This herbivore evolved to look very much like a modern rhinoceros, with stubby legs, a short neck, and teeth well adapted to eating tough grass (it may also have been equipped with a short, elephant-like proboscis at the end of its snout).

The vertebrae were equipped with high apophyses, which most likely supported the massive weight and muscles as well as its powerful head. But these creatures were so superb, they were so much more like of hippopotamuses, the way the wallowed. Despite their heavy size, *Toxodon* was a fairly fast mammal for its overall size, enough to keep pace with a Safari Jeep for at least a short time.

English national historian Charles Darwin discovered the fossils of *Toxodon* when he journeyed to South America sometime in the 1800s. Rather than finding the full skeletons, he only found their skulls instead. And in his own words written in his journal "*The Voyage of the Beagle*", he wrote:

### Behavior & Traits

*Toxodon* was initially believed to have been an aquatic animal, much like a manatee, dugong, or sea cow. However, after examining the proportions of its femur and tibia, as well as the position of its head, below the top of the spinal column, paleontologists realized that it had features similar to terrestrial animals, such as elephants, rhinos, and hippos. The fossils were also usually found in arid and semi-arid areas, typically an indication of primarily terrestrial life. However, they were indeed related to the hippopotamus.

*Toxodon* had broad jaws that were filled with bow-shaped teeth and incisors. These teeth would have allowed the animal to tear through and bite off the plants and leaves.

Much like its contemporary *Macrauchenia*, *Toxodon's* relationship to living mammals is uncertain. It falls into the larger clade of Notoungulata, literally Southern Ungulates, but the placement of this group within placental mammals is highly uncertain. They maybe have a close relationship with animals in the group Afrotheria but research in mammalian systematics is only beginning to be able to evaluate that, and other hypotheses. *Toxodon* would have had a very unusual gait, due to its peculiar proportions. It may have galloped to escape predators, but like a rhino, it probably relied more on its size as protection against predators.

Like many herbivorous animals, *Toxodon* lived and traveled in giant herds. They were also as dangerous as hippos, which are the most dangerous animals in Africa. *Toxodon* also needed to wallow in the heat of the day, just like hippos, meaning they had something of an amphibious lifestyle.

## Trivia

* The sound effects of *Toxodon* are that of bear, bison, bull, camel, cow, hippopotamus, rhinoceros, and walrus sound effects.
* *Toxodon* was the second-largest South American mammal to brought to the park, the other one is the *Megatherium*.