Kangaroos are iconic Australian marsupials that are well known for carrying their joeys (baby kangaroos) around in their abdominally located pouches. This has led many people to wonder – could a full grown human actually fit inside a kangaroo’s pouch?
If you’re short on time, here’s a quick answer to your question: While baby kangaroos can fit inside their mother’s pouches, a full grown adult human would not be able to squeeze into a kangaroo’s pouch due to issues with size limitations.
Anatomy of a Kangaroo Pouch
Location and Structure
A kangaroo’s pouch is located on their belly and is a distinguishing feature of marsupials. It is a complex and ingenious structure that allows female kangaroos to transport, nurture, and protect their joeys (baby kangaroos).
The pouch functions via a muscle structure that allows it to open and close at will. Inside the pouch are teats that allow newborn joeys with an undeveloped digestive system to access their mother’s milk.
The teats expand in number and size to accommodate the joey’s growth. By about 30 weeks, the joey achieves independence and satisfies its nutritional needs by eating vegetation. At this stage, it will begin the process of vacating the pouch permanently.
Expanding Capabilities
The kangaroo pouch is remarkably expandable to accommodate the rapid growth of joeys. At birth, joeys are about the size of a jellybean – just 2.5 cm and 2 g! After one year, a red kangaroo joey achieves an average weight of 10 kg.
During this developmental period, the kangaroo pouch expands accordingly, aided by its elasticized openings and accordion-like folds in the lining. This allows the joey adequate room to grow until it is ready to emerge and hop around outside the pouch.
Truly, the intricate design and flexibility of the marsupial pouch enables the impressive development of such tiny, helpless newborns into active juvenile kangaroos.
Kangaroo Joeys vs. Humans
Joey Size and Development
Kangaroo joeys are extremely small and underdeveloped when they are born. Newborn joeys are about the size of a jellybean, usually weighing less than 1 gram and measuring just 2.5 cm long (about 1 inch). At birth, a joey is essentially still an embryo, its organs and limbs not yet fully formed.
It has no hair, is blind and deaf, and cannot regulate its own body temperature.
Once born, the tiny joey makes an incredible journey to reach its mother’s pouch. Using its strong forelimbs, it climbs through the female kangaroo’s fur up to the pouch, where it latches onto a teat for the remainder of its development.
For the next several months, the joey continues its development protected in its mother’s pouch.
As the joey grows within the pouch, it undergoes an amazing transformation. Its organs, bones, muscles, limbs, fur, eyes and ears progressively develop. At around 190 days old, the joey will open its eyes for the first time and start to peek out from its mother’s pouch.
By 8 months old, it has grown substantially to around 2.5 pounds (1.1 kg) in weight and 12 inches (30 cm) in height. At 10-11 months old, the joey will permanently leave the pouch, though it continues to nurse until about 15-17 months old.
Average Human Size
In contrast to the tiny jellybean-sized kangaroo newborn, the average size of a human baby is dramatically larger. According to the WHO, the average newborn human weighs about 7.5 pounds (3.5 kg) and measures 20 inches (50 cm) in length.
That means a human newborn is already over 7,500 times larger than a newborn kangaroo!
Not only are we bigger at birth, but humans continue to grow substantially larger than a kangaroo over a lifetime. The average adult male human in the US stands at around 5 feet 9 inches (175 cm) and weighs 197 pounds (89 kg).
The average female reaches 5 feet 4 inches (162 cm) and 170 pounds (77 kg).
That’s in contrast to the Eastern Grey Kangaroo, one of the largest kangaroo species, which reaches heights of 5 to 6 feet (1.5 – 1.8 meters) and weights of 90-200 pounds (40-90 kg). The Red Kangaroo is the largest, with heights up to 2.1 m and weights around 200 pounds (90 kg) for males.
| Newborn Weight | Newborn Length | Adult Weight | Adult Height | |
|---|---|---|---|---|
| Human | 7.5 lbs | 20 in | 170-197 lbs | 5’4″-5’9″ |
| Eastern Grey Kangaroo | 0.001 lbs | 1 in | 90-200 lbs | 5′-6′ |
So while kangaroo joeys may one day grow large enough to fit a human infant inside their pouch, a full grown adult is far too large! A human would have to shrink down to the size of a thumb or jellybean to ever squeeze into a kangaroo’s cozy pouch.
Size and Weight Restrictions
When considering whether a human could fit inside a kangaroo’s pouch, the size and weight restrictions are important factors to examine. Here’s a closer look at the limitations:
Kangaroo Pouch Dimensions
The kangaroo’s pouch is specifically designed to carry joeys (baby kangaroos). An adult red kangaroo’s pouch measures about 35.5 cm long by 21 cm wide (approximately 14 inches by 8 inches). This provides enough space for a hairless, underdeveloped joey that is only about 2.5 cm (1 inch) long at birth.
However, it would be much too small for an adult human which is obviously many times larger in size.
Pouch Weight Limits
In addition to size constraints, there are also weight restrictions to consider. Kangaroos are strong animals but still have limits in terms of what weight their pouch can safely hold. When first emerging from the pouch at around 235 days old, red kangaroo joeys weigh only around 2-3 pounds.
Carrying anything heavier could pose a health risk for the kangaroo.
Of course, even a small adult human would be far too heavy. The average adult woman in the US weighs around 170 pounds while the average adult man tips the scales at nearly 200 pounds. This far exceeds what a kangaroo’s birthing pouch is designed to handle.
Comparative Weight Capacity
To further illustrate the vast weight discrepancy, below is a useful comparison of estimated pouch weight capacities:
| Animal | Pouch Weight Limit |
|---|---|
| Red Kangaroo | 5-10 lbs max |
| Koala | Not designed for carrying weight |
| Wombat | None (does not have a full pouch) |
As we can see, the kangaroo has a maximum pouch load far below what any human would weigh. Their pouches play a wonderful role in raising their offspring but remain much too small to transport an grown person.
Theoretical Possibilities
Could a human actually fit inside a kangaroo’s pouch? Let’s explore some theoretical possibilities.
Size Comparisons
An adult red kangaroo can stand over 6 feet tall. Their pouches are approximately 12 inches deep and 10 inches wide when expanded. Meanwhile, the average height of an adult human is 5 feet 9 inches for males and 5 feet 4 inches for females.
Considering average heights and pouch dimensions, it’s highly unlikely a full-grown human could squeeze into a roo’s pouch.
However, a small child perhaps could fit inside. Veterinarians sometimes need to access the pouches of injured female kangaroos, and have found that children under 3 years old can generally fit inside without much issue.
But it would still be extremely uncomfortable for a human child curled up in the pouch of a standing kangaroo. Not exactly a joyride!
Safety Issues
Beyond size comparisons, there are other safety issues to consider. Kangaroo pouches contain sensitive mammary glands which feed baby joeys. Having a human inside could potentially injure the mother kangaroo. The close contact could also facilitate zoonotic disease transmission to the human passenger.
So for health and ethical reasons, pouch joyriding is inadvisable even if physically possible.
Joey Jealousy
We must also remember that kangaroo pouches are not meant for humans – they are specifically adapted to raise joeys! Mother kangaroos can have a joey in their pouch while also having another joey suckling outside the pouch.
If a human child was inside, any joeys would surely be jealous of the intruder occupying their rightful pouch space. 😾 The roo mom likely wouldn’t take too kindly to an outsider hogging room in her nursery either!
Conclusion
While creative works of fiction may depict humans crawling into kangaroo pouches, anatomically it is quite impossible for an average sized human to fit inside a kangaroo’s pouch in real life situations.
However, the amazing expandability of the kangaroo pouch to accommodate growing joeys is certainly something to be marveled at in the natural world.
