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How are platypuses and echidnas alike?
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platypus
The duck-billed platypus (Ornithorhynchus anatinus), or duckbill, is common in the waterways of eastern Australia.
Platypuses and echidnas are both members of the order Monotremata, the most ancient living group of mammals. They share several fundamental characteristics that distinguish them from other mammals:12
- Egg-laying: Both animals are oviparous, meaning they reproduce by laying eggs rather than giving birth to live young.12
- Anatomy: The name "monotreme" means "one-holed," referring to the fact that both sexes possess a single opening at the rear of the body used for both reproduction and excretion.12
- Skeletal Features: They share primitive skeletal traits, such as specific characteristics of the shoulder girdle and skull, which have been lost in other living mammalian groups.2
- Sensory Capabilities: Both the platypus and the echidna possess electroreceptors, which they use to detect electrical signals in their environments.13
While they share this ancient ancestry, they have evolved into distinct forms to occupy different ecological niches, with the platypus being a semiaquatic carnivore and echidnas being terrestrial insectivores.12