Kangaroos

In this episode, we introduce the podcast and explore facts about kangaroos.

As mentioned, should you wish to support Kangaroos Alive, you can find them here: https://www.kangaroosalive.org/ 

Transcript

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Welcome to the Animal Archives. I'm your host, James Vincenza. In each episode, we will explore facts around a particular type of animal. This can mean an animal family, where we discuss a group of closely related genera that share many traits. Alternatively, we might look at a genus, which is a group of closely related species. Or we may investigate one species, a unique type of animal that can breed with its own kind to produce fertile offspring. In this episode, we will investigate my favorite animal family, kangaroos and wallabies. This group of species belongs to the family Macropodidae, or Macropods. Macropodidae is the Latin translation of bigfoot, which makes a lot of sense. By this I don't mean they are more assertive and resilient than invertebrates, but rather they have an internal skeleton and a spinal column. Macropods are also mammals, so they have fur. Mothers produce milk and give birth to live young, as in, they don't lay eggs. Like birds, mammals are also warm-blooded. Warm-blooded animals or endotherms are creatures that can regulate their internal body temperature independently of the outside environment. There are three groups of mammals monotremes, which are egg-laying mammals like the platypus, marsupials, which are pouched mammals like the kangaroos, and placentals, which are all other types of mammals, such as us humans, for example. I aim to keep my episode short and succinct, so without further ado, let's dive into the facts specifically about kangaroos. There are four primary large species of kangaroo in Australia. The most iconic of these is the red kangaroo, which is the heaviest and largest species. There is also the eastern grey kangaroo, the western grey kangaroo, and the antelopine wallaby. Kangaroos are the largest living marsupial on the planet. Kangaroo height varies among species, but the largest species, the red kangaroo, can stand at an impressive 6 feet tall from head to tail, with males weighing approximately 200 pounds. Some have even been recorded at 8 feet tall. Altogether, there are 60 species of kangaroo and wallabies worldwide, and while we've established that the red kangaroo is the biggest, there is also the musky rat kangaroo, which are typically smaller than a rabbit. Not all kangaroos keep their feet on the ground either. The tree kangaroo is adapted for life in the rainforest canopies of New Guinea, Indonesia, and Queensland in Australia, their long tail helping them reach from one branch to the next. Other species typically don't live as long. We will focus on the red kangaroo in this episode. A kangaroo has large feet with powerful hind legs which help it jump an impressive 30 feet and heights of up to 10 feet in a single bound. They can also reach speeds of 30 to 40 miles per hour but comfortably hop at about 16 miles per hour. Kangaroos are the only large animals that move primarily by hopping. Their large muscular tail is used for balance in conjunction with their large feet, but the design of these appendages prevents them from moving backwards. In fact, these iconic animals feature on Australia's coat of arms as a symbol of moving forwards and never backwards. While they don't move their legs backwards on land, kangaroos are very good swimmers. A kangaroo will move its legs independently in a motion it cannot do while hopping on land. Their powerful tail acts as a rudder and paddle, sweeping from side to side in a horizontal motion to help drive the body forward and maintain upright stability. Kangaroos have been known to lure their enemies into water where they will use their powerful front paws to drown the pursuing predator. You definitely don't want to get on the wrong side of a kangaroo. They have the same bite force as a grizzly bear, which is six times that of a human. Also, their paws have a swiping force eight times that of a human. They make excellent boxers, which explains why the boxing kangaroo is an iconic Australian image in pop culture. This is typically a cartoon image of a red kangaroo wearing boxing gloves. According to researchers, kangaroos are left-handed. The red kangaroo has been observed using their left paw 95% of the time to complete important tasks such as for eating or grooming. They usually use their right paw for strength and their left for precision. This challenges the assumption that handiness is unique to primates. Their young, called joeies, are born only about 33 days after a successful mating. They are tiny when born, roughly the same size as a jelly bean. At birth, the blind joey will attach to the nipple inside its mother's pouch where it will live and feed for the next 6 to 8 months until it is grown enough to leave the safety of the pouch. Interestingly, a fetus can go dormant if their mother becomes pregnant while she already has a joey in her pouch. Once that joey leaves the pouch, hormonal signals are sent to start fetal development of the next joey. This is a process known as embryonic diapause. While joeys might look clumsy as they adapt to life outside the pouch, they know just where to go if there is danger. To seek safety, a young joey will somersault back into their mother's pouch. Kangaroos typically live in a social group known as a mob, which can contain over 50 members. Male kangaroos can weigh twice as much as a female, and they tend to have more developed chests and forearms. This difference between the sexes is known as sexual dimorphism. The mob mostly consists of females and their joeys. Males exist in a dominance hierarchy, which means that there is a dominant male within the mob. This dominant male, known as a boomer, will take it upon himself to prevent other males from mating with females. Fights inevitably break out between the males vying to climb the ladder and take control of mating rights. In these fights, male kangaroos will lean back on their sturdy tail and they box with each other. Kangaroos are herbivores. To help with digestion, they will regurgitate their food before chewing and swallowing again. They have specialized teeth that help them break down grasses and leaves effectively. Despite a similar diet to ruminants, or cows, their chambered stomachs are different enough to help them emit only 27% of the methane produced by cows. When they aren't hopping around, you can normally find kangaroos lounging in the shade. Red kangaroos live in Australia's hot and arid desert zones, where rainfall is almost half the amount that falls on Australia as a whole each year. Temperatures can reach as high as 40 degrees Celsius. Unlike humans, a kangaroo's sweat glands only activate when they exercise to prevent excessive water loss in their dry habitat. So kangaroos lick their forearms as a method of evaporative cooling. By spreading sliva on their forearms, they create a wet layer that works the same way sweat does, helping them to lower their body temperature. Joeies learn this forearm licking behavior by imitating their mothers. Kangaroos have a large network of veins right beneath the skin of their forearms. When they are hot, blood circulation in this area is high, which helps get rid of a lot of heat. Also, the skin on their forearms is very thin, which helps the heat from the veins dissipate to the surface. However, as climate change continues to warm Australia, this adaptation might not be enough to help the animals survive. They might have to cool their bodies down even more by licking their forearms more frequently. Yet, if they lick too much, then they could become dehydrated from losing too much water as sliva. Despite being iconic, kangaroo killing quotas are in the millions each year as their meat and skins are exported to over 70 countries. In 2023, Australia's government allowed for the killing of up to 5 million individuals. These gorgeous animals are temporarily blinded by light before being shot by hunters and are sometimes left to bleed out. Worse than this, orphan joeys can be bludgeoned to death or are left to die due to the elements of nature or by starvation. Some action has been made to prevent this. For instance, the New York State Legislature has introduced a bill banning the sale and manufacture of kangaroo leather throughout the state. More needs to be done, however, and there are charities fighting for the ethical treatment of kangaroos, such as Kangaroos Alive. If you would like to learn more about the work Kangaroos Alive does and support them, there is a link available in the episode description. While this episode focused on kangaroos, my next episode will home in on a placental mammal, the sloth. The roadmap will then take us to a particular type of bird. Once we've covered warm-blooded animals, we will investigate cold-blooded animals, which include the classes reptiles, amphibians, and fish. Finally, we will visit invertebrates, animals without a backbone and having an external skeleton. And these include arthropods, molluscs, and analids, to name a few. My plan, therefore, is to visit eight very distinct animals in the first eight episodes, all of whom are very different from one another and help emphasize the natural diversity of our wonderful planet. We will discover natural diversity episode by episode. Thank you for listening to the very first episode of the Animal Archives. Should you wish to be kept updated with future episodes, then you can follow us on Instagram using the tag the dotanimal.archives. Thanks again. Until next time. Goodbye.