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What are the mammals that lay eggs

Did you know that there are currently 5 species of mammals that lay eggs ? It is strange to say that there are oviparous mammals , since one of the main characteristics that define mammals is the presence of breasts and nipples to suckle the young after birth. However, in the distant continent of Oceania, a group of oviparous mammals represent the exception within the viviparous reproduction of mammals.

If you want to know the name of this intriguing group of animals, as well as their main characteristics, list of species and their state of conservation, in this AgroCorrn article we tell you which are the mammals that lay eggs .

You may also be interested in: Are mammalian animals oviparous or viviparous?

What are egg-laying mammals called?

Monotremes is the name that the science of taxonomy has attributed to the curious and small group of mammals that lay eggs. Monotremes have inhabited the Earth since the beginning of the Cretaceous , about 110 million years ago, and are currently considered one of the strangest and most enigmatic groups of animals. If we analyze the evolutionary history of monotremes (Prototheria subclass) we will discover that they share the same origin with two very prominent groups of mammals: marsupials (Metatheria subclass) and placental mammals (Eutheria subclass).

However, the main characteristic that defines and differentiates monotremes from other mammals is their ability to lay eggs, thus lacking body organs associated with suckling their young, such as breasts or nipples. Once the young hatch the protective egg, the monotreme females feed them with nutritional substances that they excrete through their own skin pores.

Learn more about these curious mammalian animals that lay eggs , in this other AgroCorrn article in which we talk about Monotremes: characteristics and examples .

What are the mammals that lay eggs – list

Now that we know what is the peculiar group of mammals whose young hatch from eggs, let’s put a first and last name to the species that currently belong to this group, the monotremes. These are the egg-laying mammal species that still exist:

  • Platypus ( Ornithorhynchus anatinus ).
  • Short-nosed Echidna ( Tachyglossus aculeatus ).
  • Western long- beaked echidna ( Zaglossus bruijni ).
  • Eastern long-nosed echidna ( Zaglossus bartoni ).
  • Attenborough’s long-nosed echidna, or of the Cyclopses ( Zaglossus attenboroughi ).

Below, we present detailed information on each of these species, in order to learn more about the main characteristics and the current state of conservation of each one of them.

Platypus (Ornithorhynchus anatinus), the best-known egg-laying mammals

This is probably the best known monotreme in the world. These are the main characteristics of the platypus :

  • Its characteristic duck snout, as well as its curious otter and beaver tail legs, make it one of the strangest-looking mammals .
  • This curious combination of limbs and beak is perfectly designed for platypus to live in aquatic habitats . In this way, the interdigital membranes of its legs and its beaver tail allow it to be great swimmers, while its duckbill is really useful for catching small aquatic invertebrates on which they feed.
  • Another of the surprising characteristics of platypus is the presence in males of spurs with poisonous glands on their hind legs, making them one of the few poisonous mammals in the world.
  • At present, platypus inhabit only and exclusively in the eastern part of Australia and on the island of Tasmania, their conservation status being near threatened (NT).

Short-nosed Echidna (Tachyglossus aculeatus)

The echidna short snout , to the contrary that the platypus are monotremes terrestrial habitat and these are their characteristics:

  • They are small in size, between 50 and 75 centimeters in length and their appearance can be assimilated to that of hedgehogs, since they have a covering of thorns on their body.
  • The main characteristic of this species of terrestrial monotremes is the presence of a short and thin snout , devoid of teeth, which they use to feed on ants and termites, their favorite food diet.
  • To find short-beaked echidnas in their natural habitat, we should visit the islands of New Guinea, Tasmania or Australia, where these monotremes inhabit tropical and subtropical forests and grasslands.
  • The current conservation status of short-beaked echidnas is of Least Concern (LC).

Long-nosed echidnas (genus Zaglossus)

The last three species included in the group of monotremes belong to the genus Zaglossus. They are commonly known as long-snouted echidnas and, depending on their distribution within the island of New Guinea, 3 different species are distinguished :

  • Eastern long-nosed echidna ( Zaglossus bartoni ).
  • Western long- beaked echidna ( Zaglossus bruijni ).
  • Attenborough’s Long-nosed Echidna, or Mountain Cyclops (Zaglossus attenboroughi ) .

These are the main characteristics of long-snouted echidnas :

  • Like the short-snouted echidnas, described above, the body of the long-snouted echidnas has numerous spines or quills , as well as a toothless snout suitable for insectivorous feeding of the animal.
  • As their name suggests, these three species of the genus Zaglossus are characterized by a longer and finer snout than that of their short-snouted relatives ( Tachyglossus aculeatus ).
  • These egg-laying mammals usually have only 1 young per clutch , and their life expectancy is usually between 30 to 50 years.
  • Currently, long-snouted echidnas suffer the loss and degradation of their natural habitat, due to the occupation of activities such as agriculture, hunting or even sports activities within the natural range of these species. In addition, many are hunted for their meat consumption.
  • Therefore, the species Zaglossus attenboroughi and Zaglossus bruijni are in critical conservation danger (CR), while Zaglossus bartoni presents a vulnerable status (VU).
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