Old World monkeys primarily inhabit Africa and Asia.

The World Health Organization is working to improve public health worldwide.

She is conducting research on the world's oldest profession.

He is always hanging out with bad friends. Truly, birds of a feather flock together.

He is an expert in paleoanthropology, conducting research on the origins of mankind.

Rodents are widely distributed around the world.

He is an expert in primatology and is engaged in the study of gorilla behavior.

Odd-toed ungulates include mammals such as horses and camels.

Even-toed ungulates are a large group of animals that include some livestock such as cows and sheep.

He is famous as a countertenor singer.