My Science School

The duckbill platypus uses its cheek pouches to store food. Its pouches come in handy when it goes down to the bottom of the river to gather its food, mainly insect larvae, water snails and crustaceans.

These Australian mammals are bottom feeders. They scoop up insects and larvae, shellfish, and worms in their bill along with bits of gravel and mud from the bottom. All this material is stored in cheek pouches and, at the surface, mashed for consumption. Platypuses do not have teeth, so the bits of gravel help them to “chew” their meal.

 

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The walrus has a pouch on its throat, which inflates with air and props the animal up when it goes to steep in an upright position in the water.

The only natural predators for walruses are polar bears, orcas and humans.

Adult females are generally smaller than males, with an average weight of about 1,900 lbs and an average length of approximately 9 feet.  Calves of both sexes weigh between 100 to 150 pounds and are about 4.5 feet in length.

The scientific name for walrus, Odobenus rosmarus, means “toothwalkers.”

Adult Pacific walrus can eat up 4.2 to 6.2 percent of their total body weight (1760-4000 pounds) each day – that’s between 74 and 250 pounds of food per day!

 

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The hamster has an elongated pouch on either side of its head that extend to its shoulders. The animal fills it with food it plants to eat later.

Most of the time, they fill their cheeks with food, but sometimes mother hamsters store their babies in their cheeks for protection. Hamster cheeks contain pouches that resemble small deflated balloons. As food enters, the pouch expands and retractor muscles squeeze the pouch and pull food back. 

Hamsters, like other animals, have two cheeks. Sometimes they stuff both of their cheeks and other times they only stuff one side with food. It is normal for hamsters to carry their food around or back to their beds via their cheeks. They will often continue to eat, even after filling their cheek pouches. Females may even carry or hide their babies in their cheek pouches.

 

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The pelican, for instance, has a pouch that hangs down from the underside of its long beak. The pouch is the bird’s ‘fishing net’ and can expand to hold several fish at a time.

Many pelicans fish by swimming in cooperative groups. They may form a line or a "U" shape and drive fish into shallow water by beating their wings on the surface. When fish congregate in the shallows, the pelicans simply scoop them up. The brown pelican, on the other hand, dives on fish (usually a type of herring called menhaden) from above and snares them in its bill. Pelicans do not store fish in their pouch, but simply use it to catch them and then tip it back to drain out water and swallow the fish immediately. The American white pelican can hold some 3 gallons of water in its bill. Young pelicans feed by sticking their bills into their parents' throats to retrieve food.

 

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The Eastern chipmunk, a small squirrel which lives in eastern North America, has specially adapted pouches inside its cheeks, in which it is able to hold large amounts of food at a time.

Cheek pouches are more pronounced in certain rodents, such as hamsters, yet this structure is also distinguishable on certain species of rat, like the Gambian pouched rat, of which extensive morphological investigations have been conducted. Aspects including rat pouch musculature, vascularization, and innervations were all explored and compiled through this and other studies. The widely distributed Rattus rattus is an example of the rodent family Muridae that lacks a true cheek pouch, rather, they exhibit more elastic cheeks (not true pouches) due to the organization of their cheek musculature.

Concerning the musculature, the cheek pouch is composed primarily of a developed masseter (cheek) muscle that exhibits a high tensile ability. The masseter muscle has been shown to insert into the pectoralis muscles, allowing for a higher degree of food retention. The pouch is clearly divided between a buccal (cheek) and sublingual (below the tongue) portion.

 

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The long-nosed bandicoot has a pouch that faces the rear. The direction of the pouch, however, protects the bandicoot babies from dirt and other rubbish that may enter the pouch while the mother digs for food.

Long Nosed Bandicoots have harsh, almost spiny fur. They come with built-in waterproofing fur that is flat, rather than rounded, to deflect moisture. Their fur comes out easily in an attackers mouth.

They have a reverse pouch for the protection of their young whilst digging.

 

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The quoll, koala and the Tasmanian devil also have pouches that open to the rear. Female Koalas have been described as having a ‘backward-opening’ pouch like wombats, as opposed to an upward-opening pouch like kangaroos. However, that's not strictly true. When a female Koala first gives birth to young her pouch opening faces neither up nor down, although it is located towards the bottom of the pouch rather than at the top. It faces straight outwards rather than ‘backwards’.

It sometimes appears to be ‘backward-facing’ because when the joey is older and leans out of the pouch, this pulls the pouch downwards or ‘backwards’. The pouch has a strong sphincter muscle at the opening to prevent the joey from falling out.

Many other animals have pouches but for different purposes.

 

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Marsupials are animals that have pouches to carry their young ones. They include the kangaroo, koala, bandicoot, wallaby, wombat, Tasmanian devil, Tasmanian wolf, possum and the opossum. They are found mainly in Australia. The reason why marsupials have pouches for carrying their babies is that their offspring are particularly tiny when they are born. The pouch provides them a ready supply of milk and a safe place to stay till they grow big enough to look after themselves.

The kangaroo has a pouch that opens horizontally on the front of the body. Did you know that a baby kangaroo or joey in hardly the size of a bean at birth?

Interestingly, female kangaroos are able to suckle two joeys simultaneously – one in the pouch and one outside, offering two different types of milk, as well as having an egg ready for implantation. Only female kangaroos have pouches because they do the child rearing – male kangaroos have no need for a pouch as they can’t produce milk.

 

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Odd-looking, but cuddly

The pudgy and furry wombat is one of the oddest-looking animals on Earth – rather like a pig, bear and koala all rolled into one.

There are three species of wombat: the common wombat (Vombatus ursinus), the northern hairy-nosed wombat (Laisorhinus krefftii), and the Southern hairy nosed wombat (Lasiorhinus latifrons). You will be able to see all three in Australia and Tasmania, usually in forested and mountainous area.

Marsupial

Wombats are marsupials, related to koalas and kangaroos. They usually live up to 15 years in the wild, but can live past 20 and even 30 years in captivity. Rotund, with stubby tails, short ears and tiny eyes, wombats grow to around one metre in length and weigh anything between 20 and 40 kg. their fur is either sandy brown or grayish-black and this helps them blend with the landscape – a way of safeguarding themselves from predators.

Big eaters

These animals are nocturnal and emerge from their burrows to feed at night. Being herbivores, they feed on grasses, herbs, bark, and roots. They spend a lot of time, eating. They have sharp large incisors like rodents which help them gnaw at thick vegetation. Their teeth never stop growing. But they are slow to digest their meal – it takes around 8-14 days for them to fully digest their food. But this helps them adapt to Australia’s arid conditions. Since they derive most of the moisture they require from plants, they don’t need to drink much water either. And interestingly, they are the only creatures in the world to excrete poop that is cube-shaped!

Burrowing away!

They are amazing burrowers and dig lengthy burrow systems with their razor-sharp teeth and claws. Common wombats are shy and solitary and inhabit their own burrows, while the other two species may be more social and live together in large groups in their warren.

Quick sprinters

Wombats may look plump and slow, in fact, their walk is more of a waddle. Despite their podgy bodies and stubby feet, they can run really fast – even up to 40 km/h.

Just communicate

They communicate with one another in various ways – vocalizations, aggressive displays, and markings on logs and branches made by rubbing against them repeatedly. Wombats tend to be more vocal during mating season. When angered, they can make hissing sounds.

Jellybean or joey?

Female wombats give birth to a single young one known as a joey in the spring, after a gestation period of 20-21 days. When the joey is born, it is the size of a jellybean and not completely developed. The joey climbs into it mother’s pouch right after birth to finish developing and stays there for about five to six months. Wombats are weaned after 15 months.

Once pests, now protected

In 1906, the Australian government declared wombats pests and encouraged people to kill them. From 1925 to 1965, some 63,000 wombats skins were redeemed for cash. Fortunately, this practice has stopped. All species of wombats are protected in every state except for Victoria.

Powerful posterior

Startled wombats can charge humans and bowl them over, with the risk of broken bones from the fall, besides wounds from bites and claws. When running away from predators like Tasmanian devils and dingos, wombats rely on their thick rump skin to protect them. Their rear-ends are mostly made up of cartilage, which makes them more resistant to bites and scratches. At the end of a chase, wombats will dive into their burrows and block the entrance with their posterior. They’re also capable of using their powerful backs to crush intruders against the roofs of their burrows.

Wombat facts

• A group of wombats is known as wisdom, a mob, or a colony.


• Believe it or not, wombats can jump! Some have been known to jump over metre-high fences.


• The giant wombat, an ancestor of modern-day wombats, lived during the Ice Age and was the size of a rhinoceros.


• Since 2005, Wombat Day is observed in Australia on October 22.


• Wombats have featured in Australian postage stamps and coins and ‘Fatso’, the wombat, was the unofficial mascot of the Sydney 2000 Summer Games.

 

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