Happy Mother’s Day!
We have many moms that call the Edmonton Valley Zoo home: our Grevy’s zebras, Zuri and Zari; our Bactrian camels Dolly and Marshmallow; Najoua the river otter;… we could go on and on! Now, what do you think zebras, camels, and a river otter have in common?
If you guessed that they are placental mammals, you would be correct! Placental mammals (or belonging to the subdivision “Placentalia” if you want to sound very smart and scientific) are one of three different subdivisions of mammals. They carry their young in their uterus until late in their development. Most of our zoo mammals are Placentalia.
However, there are zoo moms that have wildly different pregnancies– our Red Necked Wallabies!
Wallabies are not placental mammals, but belong to a different subdivision of mammals: Marsupials. Marsupials differ from placental mammals in that they have very short gestation periods – in the case of red-necked wallabies, only 30 days! However, when a baby wallaby is born, they are nowhere near fully developed – they are roughly the size of a jellybean, can weigh as little as one gram, and are completely blind, hairless, and helpless. After the birth, the baby (which is called a joey) crawls its way up its mother’s fur and into a pouch. There the joey will remain for at least nine more months, drinking its mother’s milk and growing stronger and bigger.
The pouch is what makes a marsupial a marsupial – it comes from the ancient Greek word μάρσιππος, mársippos, which literally means “pouch.” The vast majority of marsupials found in the world can be found on the Australian continent, including wallabies, kangaroos, sugar gliders, koalas, and Tasmanian Devils (yes, they are a real animal!). The remaining 30 percent of the world’s marsupials are found primarily in South and Central America. Only a single species of marsupial can be found in the United States (but not as far north as Canada): the Virginia opossum.
Currently, our zoo has six red necked wallabies and two of them are mothers, Grace and Dardy. However, our baby wallabies have other moms! Arvo the wallaby was hand-raised by zookeepers after his mother had difficulty caring for him. It took around the clock care, and zookeepers would take him home to care for him in a flannel bag that mimicked a mother wallaby’s pouch. For more about Arvo’s story read our post, “Meet Arvo!”
It just goes to show that you don’t have to give birth to be a mother figure in someone’s life! This Mother’s Day, give the mothers in your life a big hug, either for having a much harder and longer pregnancy than a wallaby, or for taking the time and care to help you grow like our zookeepers have for baby Arvo.