🍼 Joey
Also known as: joey, kangaroo joey, baby kangaroo, pouch young
A joey is a baby kangaroo: born about the size of a jellybean, it grows up in its mother's pouch on milk that changes as it develops.
A joey is a baby kangaroo. A red kangaroo carries it for only about 33 days, and it is born about the size of a jellybean. Straight away it climbs into its mother's pouch, latches onto a teat and starts to drink milk. It will spend almost eight months in that pouch.
A female red kangaroo has four teats, and the joey stays fastened to one of them for a long time. Its milk changes as it grows: early milk can hold as little as 9% solids, late milk up to 54%, depending on the species. The mother can even run two milks at once, one for a newborn and another for an older joey that is already starting to leave the pouch.
Around day 235 the joey leaves the pouch for good, but it keeps suckling until about 12 months. Until it is eight months old, a frightened joey dives straight back in; later you can see its head and feet poking out. The mother can also hold back her next birth until the older joey has left, a pause scientists call embryonic diapause.
Other young mammals start very differently. A foal is expected to stand and suckle within two to three hours, and a puppy is born with its eyes shut and opens them within one or two weeks. A joey does nearly all its growing on the teat: a newborn wallaby is about as developed as a human foetus of eight weeks. So its mother's milk does the work that the womb does for most other mammals.
Facts
| Animal | Red kangaroo: one young at a time, about the size of a jellybean 1 |
|---|---|
| Duration | Gestation about 33 days; in the pouch up to about 235 days; milk up to about 12 months 1 |
| Nutrition | Milk solids rise from about 9% early to about 54% late in lactation 2 |
| Main use | Two different milks at once: one for a newborn, one for an older joey 2 |
How it connects to milk
🍼 Joey ← feeds ← 🦘 Kangaroo → feeds → 🥛 Milk
Links
- Fed with milk by
- 🦘 Kangaroo
- Part of
- 🤱 Who drinks milk: young animals and feeding
Frequently asked questions
What is a baby kangaroo called?
A joey. The word is also used for the young of other marsupials such as wallabies.
How long does a joey stay in the pouch?
A red kangaroo joey leaves the pouch for good at around 235 days old. Until about eight months it dives back in when threatened. It goes on suckling until about 12 months.
Is it true that a newborn joey is the size of a jellybean?
Roughly. The Australian Museum uses the jellybean comparison for the red kangaroo. Across marsupials, newborns weigh anywhere from 10 to 750 mg, so the exact size depends on the species.
Can a kangaroo be pregnant while she carries a joey?
Yes. Red kangaroos can delay the birth of the next young until the joey in the pouch has left. This pause is called embryonic diapause.
Does a kangaroo give the same milk to all her young?
No. Red kangaroos can make different milk from different teats at once: a protein-rich milk for a newborn and a more mature milk for an older joey at foot.
Similar
🍼 Goat kid · 🍼 Lamb · 🍼 Buffalo calf · 🍼 Foal · 🍼 Donkey foal · 🍼 Reindeer calf
Sources
- Australian Museum. Red Kangaroo
- Stannard H. J., Miller R. D., Old J. M. Marsupial and monotreme milk: a review of its nutrient and immune properties. PeerJ, 2020
- Western Sydney University. Wallaby joeys and platypus puggles are tiny and undeveloped when born, but their mother's milk is near-magical