The ancestors of manatees and other marine mammals shed certain genes millions of years ago. One of those genes protects against certain harmful pesticides.

The skin of the Asian common toad is laced with a natural poison. This species is now spreading across the island of Madagascar. Predators are not likely to keep the invaders in check, a new study finds. Only one appears immune to the toad’s deadly toxin.

Dickinsonia was one of the first animals on Earth. It lived on the ocean floor 550 million to 560 million years ago. It looked like a giant version of the modern-day Trichoplax, the simplest animal now alive.

Scientists can extract DNA (parts of which are displayed on screen) from samples they picked up in the environment. They then look for patterns in this genetic material to identify which species had left it. In this way, biologists can “detect” what organisms had been around.