Animals reproduce in a variety of fascinating ways. Some species, including humans and many other mammals, give birth to live young that develop inside the mother’s body. Others reproduce through less ...

Even within the world of egg-laying animals, there is an incredible variety of reproductive strategies. Some species mate before the female lays her eggs, ensuring they are fertilized internally, ...

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, ...

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 ...