Egg-laying sharks are rare "identical twins": in the eggs of a whisker shark, two embryos emerge and become "double yolk eggs". Generally speaking, an egg has only one embryo. This phenomenon is relatively rare.
Egg-laying sharks are rare "identical twins": in the eggs of a whisker shark, two embryos emerge and become "double yolk eggs". Generally speaking, an egg has only one embryo. This phenomenon is relatively rare.