Recent findings published in the scientific journal, Current Biology, show that marsupial pouches represent a biological strategy “more evolved” than currently suggested. Marsupials are mammals who evolved to have pouches to carry their young.
Scientists long believed they represented an evolutionary step between egg-laying mammals (like the platypus) and mammals who carry their infants to term inside their bodies.
While egg-laying is regarded as the ancestral state of mammals, the majority of modern-day mammals have evolved to give live birth. Marsupials include animals such as koalas, kangaroos, and opossums. When marsupials give birth, their young emerge in an embryonic state. They then grow to maturity in their mother’s pouches.
Marsupial pouches are a developmental strategy. This strategy is different from mammals whose offspring develop to maturity inside their bodies. Mammals that do this include humans, zebras, dogs, and whales.
They are known as placental mammals. Both Marsupials and placental mammals evolved from a common ancestor. Scientists believe this common ancestor existed around 160 million years ago.
Before this study, scientists believed that placental mammals represented an evolutionary stage further from this common ancestor. However, this study showed surprising results. Researchers scanned the skulls of various marsupials and placental mammals as they were developing.
By doing this, the study’s authors were able to conclude that, in terms of gestational strategy, placental mammals are closer to the common ancestor than marsupials. So marsupial pouches are more advanced in evolutionary terms!
This study helps to dispel the scientific stigma surrounding marsupials. Rather than being less evolved than other types of mammals, their developmental strategy represents a greater divergence away from their common ancestor.
This finding could have great implications for marsupial research and help dispel historic prejudice which thought of them as intermediate mammals. Greater appreciation for marsupials could help spur Conservation efforts.
Many marsupials are currently endangered and face a growing threat of extinction due to habitat loss, Climate change, and hunting.
Sign this petition to Tell Australia to Stop Logging in Endangered Koalas Habitats!
This article by Willow Lynn was first published by OneGreenPlanet on 23 July 2023.
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