Adaptive Radiation

The first evidence of modern mammals in the fossil record dates back to about 70 million years ago. If you look back at the separation of Gondwana, you'll see that Madagascar was completely separated from any other landmass almost 10 million years earlier.

When the first mammals arrived in Madagascar, there were already animals who inhabited the island. The new arrivals had to find niches where they could access the resources they needed to live, or successfully out-compete other animals. The descendants of these first arrivals took on a wide diversity of forms over time, adapting to fill a variety of different ecological roles, a process called adaptive radiation.

Below are few species of a group of Malagasy mammals called tenrecs. Match each tenrec below with the animal that plays a similar ecological role on the African mainland.

Some Malagasy animals have developed characteristics similar to those of unrelated animals in other parts of the world, a process called convergent evolution. Streaked tenrecs, for example, are covered with sharp barbed hairs similar to porcupines. When threatened, they'll raise these hairs around the neck and head-butt a predator - embedding spines in their attacker. Even more amazingly, they can vibrate quills together to create ultrasonic sounds that other tenrecs can hear up to 12 feet away!