These pouches, which are part of the frog's lymphatic system, extend along the side and belly, and bulge as the tadpoles grow into frogs. In contrast to invertebrates, fish, and amphibians, nearly all bird species care for their young. Birds are the only group in which it is most common for both parents to pitch in to care for their young. While females usually are responsible for most of the care, there are some species in which the males single-handedly incubate the eggs and care for the hatchlings. These birds have young that are precocial, which means that, like ducklings, they are down-covered and able to move freely immediately after hatching.
Some ratites care for more than one clutch at a time.
After incubating the eggs for about five weeks, the male leads and defends his hatchlings for another few weeks. She lays up to five eggs in each nest, and the males incubate them for four weeks and then defend the hatchlings until they can fly. To distract predators, males crouch and slap their wings and feet against the ground or floating plants. Female jacanas are quite a bit larger than the males and dominate them completely. This all goes to show us that we can't second-guess parenthood in the animal kingdom.