Deer, Giraffes, and Camels

By | September 9, 2016

Around 20 million years ago, Earth’s forests began to shrink as a new habitat—grassland—took over. This change encouraged the spread of plant-eating hoofed mammals, many of which had special stomachs able to digest grass and other rough plant foods.
Such plant-eaters became very successful, and many species evolved, including not only the deer, giraffes, and camels on these pages but also sheep, goats, cattle, buffalo, llamas, antelope, and hippos.

FAMILY FACT FILE

Key features
■ After swallowing food, deer, giraffes, and camels bring it up from the stomach to chew a second time.
■ Three or four stomach chambers
■ Head often bears horns or antlers
■ Feet have even number of hoofed toes (except camels, which don’t have hooves)

When
Even-toed hoofed mammals appeared about 54 million years ago, became widespread and common about 20 million years ago, and still exist.

Megaloceros (MEG-ah-LOSS-er-oss)

megaloceros


When: 5 million–7,700 years ago (Late Neogene)

Fossil location: Eurasia

Habitat: Plains

Length: 10 ft (3 m)

Diet: Plants

One of the largest deer ever known, Megaloceros was about the size of a modern moose. The male had the most enormous antlers of all time—from tip to tip, they measured more than the total body length of a tiger. It used its antlers for display to attract females, as well as to scare off rival males. Like other deer, it shed its antlers every year. Megaloceros was hunted by primitive humans, big cats, and wolves, and died out 10,000 years ago.

Giraffokeryx (jee-RAFF-oh-CARE-icks)

giraffokeryx-3


When: 16–5 million years ago (Neogene)

Fossil location: Asia, Europe, Africa

Habitat: Grasslands

Length: 5.1⁄4 ft (1.6 m)

Diet: Plants

Today, there are only two living members of the giraffe family: the giraffe and the okapi. In the past there were many more, including Giraffokeryx. It had two pairs of pointed, furry horns—one pair on its head and another on its snout. At the back of its jaws were ridged teeth, well suited to grinding tough plants.

Cranioceras (CRAY-knee-OSS-eh-rass)

cranioceras-1

The horns of Cranioceras may have been more like the fur-covered horns of giraffes than the bony antlers of deer.


When: 20–5 million years ago (Neogene)

Fossil location: N. America

Habitat: Woodlands

Length: 3 ft (1 m)

Diet: Leaves

A hoofed, cud-chewing mammal, Cranioceras was a close relative of early deer and giraffes. Males had two short, straight horns over their eyes and a thick, blunt horn that curved up at the back of the head. Injuries on fossilized horns suggest they were used in fights over mates or territories.

Aepycamelus (AY-peeh-CAM-ell-us)

aepycamelus


When: 15–5 million years ago (Neogene)

Fossil location: USA

Habitat: Woodlands and grasslands

Length: 11 ft (3 m)

Diet: Plants

Aepycamelus was a camel but looked a little like a giraffe—it was very tall, with a long neck. It could run fast on its long legs, each of which had two hoofed toes with broad pads underneath. Like all camels and giraffes, it walked by swinging its left legs together and then its right legs, a style of walking known as “pacing.” It probably fed on leaves more than grass.

Stenomylus (STEN-oh-MILE-us)

stenomylus


When: 25–16 million years ago (Late Paleogene–Early Neogene)

Fossil location: USA

Habitat: Grasslands

Size: 2 ft (60 cm) tall

Diet: Grass

Stenomylus was a small camel. Its neck, legs, and body were delicate and slender, more like those of a gazelle than a modern camel. Unlike modern camels, Stenomylus walked on tiptoe. It had huge molar teeth with very deep roots. These must have been used for chewing very tough or gritty plants, as fossilized teeth show signs of extreme wear during the life of the animal.

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