Maybe you've seen a "mermaid's purse" while walking on the beach. Not actually an accessory for the mythical creature, these small casings are the eggs of sharks and their relatives. For around 455 ...

We’ve all heard the phrase, “a fish out of water,” but these fish take it literally. As you can see in this YouTube video, splash tetras lay their eggs on a leaf overhanging the water. Only 1% of the ...

European cuckoos lay very different eggs depending on the host species. Genetic analyses have revealed how this adaptation is inherited without leading to speciation. Bright blue, white, greenish, ...