Animals That Lay Eggs (Oviparous Animals)

Animals vary from each other when it comes to the modes of reproduction. On this basis, one could classify them as oviparous and viviparous.

Animals that lay eggs are called oviparous. In this case, the eggs’ fertilization and development don’t occur within the female’s body, and the eggs hatch outside. In the case of viviparous reproduction, the embryo develops in the mother’s body resulting in the birth of live young.

Ovoviviparous is the third form and a mid-way between the oviparous and viviparous methods. Here, the eggs are hatched in the mother’s body, fertilized internally, and the young are born. All birds lay eggs; however, when it comes to mammals, just a handful, including the platypus and echidnas, are egg-layers. When speaking of amphibians, reptiles, and fish, most are oviparous, while few are viviparous and ovoviviparous.

List of Egg-Laying (Oviparous) Animals

Popular Birds that Lay Eggs

All members of the avian world lay eggs. Here is a list of popular flight and flightless egg-laying birds

Name of the Birds	Description
Ostrich	The ostrich eggs are the largest of any living bird. The egg shells are glossy with creamy-white coloration. In the past, the shells held special significance, used as containers and even decorative pieces.
Emu	Emus lay eggs during winter from November to March. Around 30 eggs are laid during the season, at a gap of every 3-4 days.
Penguin	The king and Emperor penguin lay a single egg at a time. All other penguin species lay two eggs in a gap of 24-48 hrs.
Bald Eagle	Bald eagles lay 1-3 eggs in a clutch that appear oval-shaped and dull white. They are more rounded than a chicken’s egg.
Chicken	The eggs are oval-shaped, with bumps, crusts, or ridges on the shell. They are mostly rounded, while some eggs could appear much more pointed. Chicken eggs are high in nutrition because of their rich protein, iron, vitamin, and mineral content.
Peacock	The eggshells of ducks mostly appear white but may come in other colors, like pale gray, black, blue, or green.
Duck	The shells of ducks’ eggs mostly appear white but may come in other colors too like pale gray, black, blue or green.
Raven	The raven’s egg is unique, varying in shades of green to olive and blue to a mottled appearance.

Animals that Lay Eggs but are Not Birds

Name of the Animals	Class	Description
Duck-billed Platypus	Mammal	It is one of the few mammals that lay eggs instead of giving birth to live young. On average, the females lay around two eggs that are small, leathery, and a little rounder than the birds’ eggs.
Echidnas	Mammal	All four species of echidnas – eastern echidna, western echidna, short-beaked echidna, and Sir David’s long-beaked echidna are the only mammals apart from the duck-billed platypus to lay eggs. The eggs are leathery and soft-shelled, weighing around 0.07 oz and having a height of 0.55 inches.
Alligators	Reptile	Female alligators lay 20-50 eggs in nests of sticks, fronds, and mud. Their eggs are oval-shaped and rounded, tapering to the end.
Crocodiles	Reptile	The eggs of crocodiles are smooth and hard. Females lay a clutch of 30-60 days that take around 80-90 days to incubate.
Turtles	Reptile	Turtles mostly lay the first clutch in 3-6 weeks from mating. The eggs of all turtles appear white or cream, with the shapes varying from one species to the other. They could either be wholly spherical or a little elongated.
Frogs	Amphibian	Almost all species of frogs are oviparous, laying eggs in warm and wet habitats. Species of the Nectophrynoides are ovoviviparous, fertilizing the eggs first, followed by the birth of toadlets. Frogs of the Nimbaphrynoides genus are viviparous, giving birth to live young.
Salamanders	Amphibian	Most salamanders lay eggs, except a few like the fire salamander and alpine salamander that give birth to live young. Those living in water all their life lay more eggs than land salamanders.
Seahorses	Fish	The male seahorses have an organ named brood pouch in their stomach. This serves as a career and can hold around 2000 eggs at a time, placed by the female. The eggs take 2-4 weeks to grow, and the male barely makes any movement during their development.
Sharks	Fish	The majority of sharks give birth to live young. Of the few that lay eggs, the prominent ones include bamboo sharks, carpet sharks, swell sharks, wobbegong sharks, and several species of catsharks.
Snakes	Reptile	Around 70% of the snake species lay eggs, mostly in dark and secluded areas. However, the remaining 30%, including the vipers, sea snakes, and boas, give live birth. Some, like the rattlesnakes, are ovoviviparous.
Lizards	Reptile	Most lizards are oviparous and reproduce by laying eggs. However, some, like the common lizard, give birth to live young. The Jackson’s chameleon is another such lizard where the mother gives birth to babies (8-30) instead of laying eggs.
Spiders	Invertebrate	All spiders lay eggs within a sac constructed with a silken web and closely resembles a cocoon.
Crabs	Invertebrate	Female crabs lay eggs once in their life. The number of eggs laid varies from one species to the other. A red crab can lay about 100,000 at a time. In contrast, hermit crabs lay 800 -50,000 eggs in a go. Hardly three to four of them survive till adulthood.
Centipedes	Invertebrate	The eggs of centipedes are spherical and shiny, varying in color from cream to brown. The females lay the eggs either in the soil or inside the hollows of the rotting logs. The eggs are susceptible to fungal attack and need special care so that they may reach adulthood.

Interesting Facts

The three-toed skink or the yellow-bellied three-toed skink has the unique ability to practise both modes of reproduction, oviparous and viviparous. It has been observed that populations near Sydney would lay eggs, while those living in northern New South Wales mostly gave birth to live young. In April 2019, researchers from Sydney University identified a female of this giving live birth and laying eggs from a single pregnancy.

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