Iguana
Predator-prey interactions are often viewed as evolutionary arms races; while predators improve their hunting behaviors and their ability to sneak up on their prey, the prey improve upon their abilities to detect and escape from their predators. The problem, of course, is that there is a trade-off between maintaining vigilance - the attention necessary to be consistently aware of others in the environment takes quite a bit of physical and mental energy - and doing all the other things that an animal must do, such as finding its own food. As a result of this trade-off, many social species,…
One hundred and seventy-four years ago, Charles Darwin first set foot on the Galapagos Islands aboard the Beagle. Since then, the islands and the unique species they house have been a source of inspiration for many an evolutionary biologist. Even so, it is gratifying to see that even now, on the bicentennial of Darwin's birth, the Galapagos have not yet finished yielding their secrets.
During Darwin's five-week stint on the Galapagos, he observed two types of iguana. One was a marine version that, uniquely for lizards, swam and fed in the ocean, and the other was a cactus-eating landlubber…