Biology 101

They need fresh water to breed, but there's nary a drop on most Galapagos Islands.

Whether a pair of lizards, a couple of Mexican hogfish or two men out behind the bar, animals often circle each other as they fight.

Sibling rivalries are serious - and deadly - for the chicks of some Boobies.

Galapagos marine iguanas are ectotherms that have to manage their surrounding environment to control their body temperature.