What Animal Lays Eggs But It’s Not A Bird?

The duck-billed platypus is an example of an animal that lays eggs but is not a bird. It is a monotreme, a type of mammal that lays eggs instead of giving birth to live young. Other examples of monotremes include the echidna and the spiny anteater. In addition to monotremes, many reptiles, amphibians, and fish also lay eggs.

Featured Answers

The platypus lays eggs like a bird but is not a bird.

Answered from Anonymous

Most amphibians, snakes, and fish lay eggs, however there are some exceptions, like boas and vipers. Monotremes are mammals that lay eggs; including the echidna, spiny anteater, and the platypus.

Answered from evynyn

What Animal Lays Eggs But It's Not A Bird?

While birds are well known for laying eggs, several other major animal groups also reproduce via eggs including reptiles, amphibians, most bony fish, sharks, and invertebrates. Each has evolved specialized eggs and reproductive strategies adapted to its environmental niche. This article explores the fascinating diversity of egg-laying across the animal kingdom.

Overview of Major Egg Laying Animal Groups

Reptiles – Most species from lizards to snakes to crocodilians lay amniotic eggs with leathery or calcified shells. Turtles and tortoises are famous for trekking overland to lay eggs in buried nesting grounds. Even venomous cobras carefully incubate their clutches.

Amphibians – Frogs, toads, salamanders, and caecilians all deposit clutches of soft, jelly-coated eggs in or very near water. Their shell-less eggs must remain moist to develop. A single female frog may lay up to 20,000 eggs per reproductive cycle!

Bony Fish – From tiny guppies to massive tuna, most fish release clouds of small eggs externally into water that are immediately fertilized by males. No parental care occurs – eggs hatch independently.

Sharks – While some species give live birth, many sharks lay eggs enclosed in tough, corkscrew-shaped egg cases that protect the embryos inside. Skates and rays also lay egg bundles known as mermaid's purses.

Invertebrates – It's easier to name invertebrates that don't lay eggs! Practically every insect, spider, mollusk, and crustacean reproduces by laying clutches of fertilized eggs numbered anywhere from two to millions.

Reptile Egg-Laying Habits

Reptile eggs share common leathery or hard shells, but species exhibit fascinating diversity in their egg-laying behavior and habitats.

Sea Turtles – Endangered leatherback sea turtles migrate 2,000 miles to lay over 100 eggs in a sandy tropical nest. Eggs incubate for 60 days.

Geckos – These tropical lizards lay pairs of soft, white eggs glued to leaves or bark. Hatching may occur in just 40 days.

Cobras – One of few snake species to vigilantly guard their 40-60 egg clutches for 60+ days until hatching.

Tuatara – This rare reptile indigenous to New Zealand lays up to 15 eggs in deep underground burrows dug near its coastal territory.

Crocodilians – Massive crocodile mothers protect their nests of 40 to 60 eggs laid near riverbanks. Eggs require 90 days incubation.

Tortoises – From Galapagos giant tortoises to box turtles, females leave eggs buried and unattended to incubate independently.

Amazing Amphibian Egg Adaptations

Most amphibian eggs lack a hard shell, so they require a moist environment to prevent drying out. But amphibians have adapted clever solutions:

  • Poison dart frogs lay eggs in damp tropical foliage, and males transport tadpoles to pools in rainwater held in bromeliad plants.
  • Darwin's frogs display remarkable parental care with fathers actually swallowing eggs and incubating them in their vocal sac for 6-12 weeks until they emerge as tiny frogs.
  • Female caecilians, a legless amphibian, retain fertilized eggs inside the oviduct where developing embryos feed on secretions. Live babies are birthed.

How Bony Fish Spawn Eggs

Spawning adaptations allow fish eggs a chance at survival:

  • Many species migrate in massive schools to ancestral waters to converge for mating season. Herring deposit up to 300,000 adhesive eggs that stick to coastal vegetation.
  • Female cichlids ready to spawn exhibit vivid red or pink bellies called oviposition stripes as visual fertility indicators attractive to males.
  • Flatfish like halibut chase each other in a dance-like courtship ritual, then females anchored in sandy seabeds release buoyant eggs that males fertilize.
  • The tiny male Argonaut octopus has a detachable arm specialized to fertilize the female's egg clusters – then he dies while she deposits them.

Invertebrates and Their Creative Eggs

Insects and other invertebrates produce eggs maximized for their environments. For example:

  • The incredible Tiny Litter Bee lays her eggs and provisions food inside empty snail shells for larvae to feed until maturity.
  • Some female octopuses like the Giant Pacific brood eggs for 4-5 months. She oxygenates them with gentle jets of water and even lets them feed on her own arm for nourishment!
  • The quaint but dangerous Blue Dragon nudibranch swallows Portuguese man o’ war jellyfish, steals their stinging cells to decorate its vivid blue egg ribbons for protection.
  • Fierce female earwigs display extensive maternal guarding, clutching eggs beneath her tail all winter then fanning and feeding hatched nymphs.

Why Did These Animals Evolve to Lay Eggs?

Reproducing via eggs offers many evolutionary advantages:

  • Protection – from predators, weather, hazards
  • Mobility – parents can transfer to optimal safe locations
  • Less burden – carrying egg clutches expends less energy than live birth over time
  • Genetic diversity – external fertilization allows mixing input from multiple mates
  • Flexibility – eggs can be adapted for land or water environments

Scientists hypothesize egg-laying first evolved 500+ million years ago in marine organisms, conferring survival benefits that led to widespread retention across many animal lineages.

Comparing Eggs Across the Animal Kingdom

While all are vessels protecting developing offspring, reptile, amphibian, fish, invertebrate, and bird eggs exhibit fascinating diversity in:

  • Shell composition – calcareous, leathery, gelatinous, soft, hard
  • Shape – oval, tapered, spherical, cluster, spiral
  • Size – from microscopic to over 4 inches long
  • Number per clutch – from 2 to 300,000!
  • Incubation – heat, moisture dependence
  • Parenting – by one or both parents, or none

This amazing range represents specialized evolutionary solutions enabling successful reproduction in diverse environments.

From Tiny Turtle to Enormous Ostrich – Egg Examples

AnimalNumber in ClutchSizeIncubation Period
Turtle2-181-5 cm60-120 days
Crocodile40-605-6 cm80-100 days
Cobra10-204-5 cm60-90 days
Tuatara8-1535 g12-15 months
Poison dart frog3-62-3 mm14-20 days
Salmonup to 4,000~5 mm55-80 days
Octopus20,000-100,0001 cm160 days
Ostrich6-1215 cm x 13 cm35-45 days


While oviparity – egg laying – is most associated with birds, reptiles, amphibians, many fish, sharks, and invertebrates also display this amazing reproductive strategy. Each group has evolved eggs specialized and optimized for its unique niches and lifestyles. From tiny gel capsules to massive leathery shells, eggs come in marvelous diversity across the animal kingdom. Yet all allow species to continue propagating in our complex biosphere.

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