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Fish generally do not incubate their eggs. However, some species mouthbrood their eggs, not eating until they hatch. Some amphibians brood their eggs. The female salamander Ensatina (Ensatina eschscholtzii) curls around the clutch of eggs and massages individual eggs with her pulsating throat. [14] Some aquatic frogs such as the Surinam toad ...
Here a Montagu's harrier chick has just hatched from its egg. Animals make use of a variety of modes of reproduction to produce their young. Traditionally this variety was classified into three modes, oviparity (embryos in eggs), viviparity (young born live), and ovoviviparity (intermediate between the first two).
In developmental biology, animal embryonic development, also known as animal embryogenesis, is the developmental stage of an animal embryo. Embryonic development starts with the fertilization of an egg cell (ovum) by a sperm cell (spermatozoon). [1] Once fertilized, the ovum becomes a single diploid cell known as a zygote.
They hold the eggs internally for several weeks, providing nutrients, and then lay them and cover them like birds. Like marsupial " joeys ", monotreme " puggles " are larval and fetus-like, [ 9 ] as like them they cannot expand their torso due to the presence of epipubic bones, forcing them to produce undeveloped young.
Precocial birds can provide protein-rich eggs and thus their young hatch in the fledgling stage – able to protect themselves from predators and the females have less post-natal involvement. Altricial birds are less able to contribute nutrients in the pre-natal stage; their eggs are smaller and their young are still in need of much attention ...
The behavior of an amphibian hatchling, commonly referred to as a tadpole, is controlled by a few thousand neurons. [4] 99% of a Xenopus hatchling's first day after hatching is spent hanging from a thread of mucus secreted from near its mouth will eventually form; if it becomes detached from this thread, it will swim back and become reattached, usually within ten seconds. [4]
Oviparous animals are animals that reproduce by depositing fertilized zygotes outside the body (known as laying or spawning) in metabolically independent incubation organs known as eggs, which nurture the embryo into moving offsprings known as hatchlings with little or no embryonic development within the mother.
In many sharks the eggs hatch in the oviduct within the mother's body and the embryos are nourished by the egg's yolk and fluids secreted by glands in the walls of the oviduct. [19] The Lamniforme sharks practice oophagy, where the first embryos to hatch consume the remaining eggs and sand tiger shark pups cannibalistically consume neighbouring ...