Vertebrate Zoology: A Study Guide - T. A. Dauda 2014

Multicellular Animals
Infraclass Eutheria, or Placental Mammals
Order Tylopoda

The suborder Tylopoda comprises large animals featuring a leathery cushion (callosity) on the third and fourth digits of both fore and hind limbs, preceded by small, slightly curved claw-like horny structures (Fig. 66). The second and fifth digits are absent. Their coat is dense and uniquely structured, protecting the animals from both scorching solar rays and severe cold.

Class="center">

Fig. 66 Tylopods (mammals of the suborder Tylopoda):

1 — dromedary (single-humped camel); 2 — guanaco; 3 — Bactrian camel (two-humped camel); 4 — vicugna.

Currently, only three wild species of tylopods survive in nature. The Bactrian camel is found in Mongolia and suffers the most from desert encroachment. The dromedary is known exclusively in a domesticated state, bred primarily in North Africa and Arabia. Humans utilize these camels for desert transport, as well as for meat comparable in quality to beef, wool, and milk with a fat content reaching up to 6.5%. Camels can go without food and Water for long periods, storing energy as fat in their humps and, as research has recently revealed, retaining water in their Blood—specifically within hygroscopic red Blood Cells. These cells can swell to three times their normal volume, releasing water into the body as needed. They also possess various other adaptations for surviving in hot climates.

Two species of humpless tylopods inhabit the mountainous regions of South America: the guanaco and the vicugna. Their domesticated forms are known as the llama and the alpaca, both utilized as pack animals.