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 ...

Snakes, like most reptiles in the world, are oviparous. This means that rather than producing live young ones, the way mammals do, snakes produce an immature single cell — an egg. Most snakes follow ...

Female lineages of European cuckoos lay eggs with colorful shells and intricate patterns specialized to deceive more than 100 avian hosts into fostering their chicks. Parasitic cuckoo eggshells show ...

Q. When we studied high school biology, our teacher said more than 99 percent of animals lay eggs and only a few give live birth. That percentage seems too high. Humans, dogs, cats and cows are ...

Why did our ancestors ditch the shell and start growing babies inside their bodies instead? In this episode of Big Ideas, from the team behind Deep Look, Niba zooms out to explore one of evolution’s ...

A curious aspect of tree frogs is that they often lay their eggs on the ground where the risk of predation by natural enemies is greater than in the trees where they live. A research team suggested ...

When you're trying to detect and identify snakes in your yard, a clutch of eggs in the grass or under a squash vine could be an indicator of snake activity. However, eggs on the ground aren't ...

DEAR JOAN: We enjoyed your story about Annie, the peregrine falcon that lives on the Cal bell tower, and it sparked a discussion about how old Annie is and how long she can keep laying eggs. We ...

European cuckoos lay very different eggs depending on the host species. Genetic analyses have revealed how this adaptation is inherited without leading to speciation. Subscribe to our newsletter for ...

A tree frog: female (larger individual below) laying eggs, which are protected by the 'foam nest' and male (smaller individual above). When it comes to laying eggs, tree frogs have some unusual habits ...