Mammals That Lay Eggs

Most mammals give birth to live young, but there are a few unique mammals that lay eggs. These special creatures are called monotremes, and they belong to an ancient group of mammals that have retained this egg-laying ability. There are only five species of monotremes in the world today, all of which are native to Australia and New Guinea. In this blog, we’ll explore these fascinating mammals, their characteristics, and answer some frequently asked questions.

Table of Contents

• Platypus (Ornithorhynchus anatinus)
• Echidna (Spiny Anteater)
  • Short-Beaked Echidna (Tachyglossus aculeatus)
  • Western Long-Beaked Echidna (Zaglossus bruijni)
  • Sir David’s Long-Beaked Echidna (Zaglossus attenboroughi)
  • Eastern Long-Beaked Echidna (Zaglossus bartoni)
• Fun Facts About Mammals That Lay Eggs
• Frequently Asked Questions About Mammals That Lay Eggs

Platypus (Ornithorhynchus anatinus)

The platypus is one of the most unusual and unique animals on Earth. As one of the few egg-laying mammals, the platypus is often recognized for its bizarre combination of features that make it look like it was put together from several different animals. Native to eastern Australia and Tasmania, the platypus thrives in freshwater habitats and has many adaptations that allow it to live both on land and in water.

• Description: The platypus is one of the most unique mammals in the world, with a duck-like bill, webbed feet, and a flat tail similar to a beaver’s. It is covered in waterproof fur and spends much of its time in freshwater rivers and lakes.
• Habitat: Platypuses are found in eastern Australia, including Tasmania, where they live near rivers, streams, and lakes.
• Diet: Platypuses feed on aquatic invertebrates, such as insects, worms, and small crustaceans, which they find by using the sensitive receptors in their bill.
• Reproduction: Female platypuses lay 1-3 eggs and incubate them in a burrow. After about 10 days, the eggs hatch, and the mother nurses her young by secreting milk from mammary glands, even though she has no nipples.
• Fun Fact: One of the platypus’s surprising features is that male platypuses have venomous spurs on their hind legs. The venom is not lethal to humans but can cause intense pain and swelling. The venom is likely used for defense or during fights with other males during the breeding season.

Echidna (Spiny Anteater)

Echidnas are fascinating, egg-laying mammals known for their spines and long snouts. While most people are familiar with the short-beaked echidna, there are actually four species of echidnas: the short-beaked echidna and three species of long-beaked echidnas. These unique animals are found in Australia and New Guinea and play important roles in their ecosystems.

Short-Beaked Echidna (Tachyglossus aculeatus)

• Description: The short-beaked echidna is the most common species of echidna. It is covered in coarse fur and sharp spines, which provide protection from predators. It has a short snout, which it uses to dig for ants and termites, its primary food source.
• Habitat: Found across Australia, Tasmania, and parts of New Guinea, the short-beaked echidna can thrive in a wide range of environments, from forests to deserts.
• Diet: Primarily insectivorous, feeding on ants, termites, and other small invertebrates. It uses its long, sticky tongue to capture prey.
• Fun Fact: The short-beaked echidna is one of the few mammals that lays eggs. After the female lays an egg, she carries it in a pouch until it hatches.

Western Long-Beaked Echidna (Zaglossus bruijni)

• Description: The western long-beaked echidna is larger than the short-beaked echidna and has a longer snout. Unlike its short-beaked relative, this species feeds mainly on earthworms rather than ants and termites.
• Habitat: Endemic to the highland forests of New Guinea, the western long-beaked echidna prefers cool, wet environments at high altitudes.
• Diet: Primarily feeds on earthworms and other invertebrates found in the soil. Its long snout and specialized tongue help it probe into the ground for food.
• Fun Fact: The western long-beaked echidna is critically endangered due to habitat loss and hunting by humans.

Sir David’s Long-Beaked Echidna (Zaglossus attenboroughi)

• Description: Named in honor of naturalist Sir David Attenborough, this species is the smallest of the long-beaked echidnas. It has a long, narrow snout and a more slender body compared to the other long-beaked species.
• Habitat: Found only in the Cyclops Mountains of Papua New Guinea, Sir David’s long-beaked echidna inhabits dense, high-altitude rainforests. It is one of the rarest mammals in the world.
• Diet: Like the other long-beaked echidnas, it primarily feeds on earthworms and small invertebrates.
• Fun Fact: Sir David’s long-beaked echidna was considered extinct until a small population was rediscovered in 2007.

Eastern Long-Beaked Echidna (Zaglossus bartoni)

Video: Taronga Zoo Sydney

• Description: The eastern long-beaked echidna is the largest species of echidna. It has a robust body, long snout, and thick fur in addition to its spines. Unlike the short-beaked echidna, its spines are shorter and less prominent.
• Habitat: This species is found in the highland forests of eastern New Guinea. It prefers cool, moist environments and is adapted to life at higher altitudes.
• Diet: The eastern long-beaked echidna primarily feeds on earthworms and other soft-bodied invertebrates. It uses its long tongue to reach into the soil for food.
• Fun Fact: Despite its large size, the eastern long-beaked echidna is an elusive creature and rarely seen by humans. It is listed as vulnerable due to habitat loss and hunting.

Fun Facts About Mammals That Lay Eggs

Monotremes are Primitive Mammals
Monotremes are considered primitive or early mammals because they retain the egg-laying trait of their reptilian ancestors, despite being warm-blooded and having fur.

They Don’t Have Nipples
Unlike other mammals, monotremes do not have nipples. Instead, they secrete milk from special mammary glands, and their young lick the milk off the mother’s skin or fur.

The Puggle
Baby echidnas are called puggles. When they hatch from their egg, they are tiny and hairless, resembling a pink jellybean. They stay in their mother’s pouch for several weeks before growing spines and fur.

Video: Taronga Zoo Sydney

Platypuses Have Venom
Male platypuses have a venomous spur on their hind legs. While the venom is not deadly to humans, it can cause intense pain and swelling.

Electroreception in Platypuses
Platypuses have specialized cells in their bill that allow them to detect the electrical signals produced by the movement of prey in the water, making them highly skilled hunters even in murky water.

Echidna Spines for Protection
Echidnas are covered in sharp spines that help protect them from predators. When threatened, they can curl into a ball, much like a hedgehog, with only their spines exposed.

Endemic to Australia and New Guinea:
All monotremes are native to Australia and New Guinea, making them unique to that region of the world.

Frequently Asked Questions About Mammals That Lay Eggs

Monotremes, the egg-laying mammals, are among the most unique creatures in the animal kingdom. The platypus and echidna offer us a glimpse into the early evolutionary history of mammals while continuing to adapt and thrive in the ecosystems of Australia and New Guinea. Understanding these remarkable animals helps us appreciate the incredible diversity of life on Earth and the various ways different species have evolved to survive.