Lesson

Australian Bats


So I thought, today, we’ll talk about Australian bats.

So, bats are the only mammals capable of sustained flight and are believed to have first flapped their way all the way to Australian shores through Southeast Asia some 23 to 34 million years ago during the Oligocene.

Since their arrival, or perhaps series of arrivals, they’ve diversified into 77 species that now call Australia home. Australian bats have since become an important part of the Australian ecosystem as they act as important pollinators of native plants, they disperse seeds over wide areas, and they also vacuum up insects by the millions on a nightly basis.

So, there are two types of bats in Australia. You’ve got your microbats and you’ve got your megabats.

As the name suggests, microbats are relatively small. Right? ‘Micro’, ‘microscopic’, ‘microbat’, small bat, and they’ve got a wing span of up to 25 centimetres and feed primarily on insects such as mosquitoes.

They use echolocation to navigate in complete darkness as well as to track down their unsuspecting prey victims whilst flying at night. That said, they still have eyes and they can still see. So, that expression ‘blind as a bat‘, meaning you can’t see, is actually somewhat biologically inaccurate.

Some species of microbats spend their days deep within caves, whilst others rest below tree bark or in man-made structures like houses and buildings, before coming out at night to hunt.

The other type of bat is the megabat. Megabats, or fruit bats or flying foxes as they’re also known, because of the diet that they eat or the fact that they look like foxes, on the other hand, they have a wing span of up to a metre, right, maybe a little bit less than a full grown adult, you know, with their arms spread out.

So, unlike their micro cousins, they don’t use echolocation, they don’t have echolocation as an ability, nor do they feed on insects. Instead, they opt for a vegetarian lifestyle eating things like fruit, blossoms, and nectar. Right? Fruit bats.

Due to their lack of echolocation, they have a really well-developed eyes and a strong sense of smell which enables them to locate food in the dark. They live in large social groups in trees called ‘camps’ or ‘colonies’.

Now, are bats dangerous? In and of themselves, bats aren’t really dangerous. You know, you might get scratched or bitten if you were to come into contact with a bat.

However, they do harbour many dangerous parasites and diseases which have proven lethal to humans in the past. Three examples include:

Paralysis ticks. One of the 70 or so ticks species in Australia, which can inject a potent neurotoxin into its host, whether it be an unfortunate bat, horse, dog, cat, or human. And there have been at least 20 deaths from these ticks in the past. And every year, 500 dogs are killed by them.

Australian Bat Lyssa virus is number two. This is a virus that belongs to the group of viruses that includes rabies, although, we don’t have rabies in Australia. However, Lyssa virus is carried by bats in Australia and anyone working with bats or likely to come into contact with them usually has the vaccination for this virus.

I remember my mum getting three of these vaccinations when I was a kid, because she was a biologist working with bats, and it was like a bright pink fluid that they were injecting.

So, the virus can be spread through bites and scratches from bats, and the early symptoms are flu-like, including headaches, fevers, and fatigue. The illness progresses rapidly leading to paralysis, delirium, convulsions, and death, usually within a week or two.

Although, the vaccine will prevent death if you receive it before or shortly after a bite or scratch from a bat, by the time symptoms arise, it’s usually too late to be cured and you are certain to die, unfortunately, and there have been three human deaths since 1996 in Australia.

The last one is the Hendra virus. Now, the Hendra virus is a virus that infects large fruit bats or flying foxes. Sometimes the virus can spread from flying foxes to horses, which can then pass on, in turn, to human beings. Usually, they’re trainers, the trainers of horses, or the vets.

The virus was only discovered following an outbreak in 1994 in a large racing stable in the suburb of Hendra in Brisbane, hence the name.

Symptoms usually arise within the first three weeks after infection, including fever, cough, sore throat, headache, tiredness, all are common initial symptoms, and it leads to meningitis or encephalitis (inflammation of the brain), which can develop causing headaches, high fevers, drowsiness, and sometimes convulsions and coma. And the Hendra virus infection can thus be fatal.

Since 1994, 81 horses have died from the infection and four human beings have lost their lives to it. The most recent occurring in 2009. There is no cure to the virus. You just have to get treatment in hospital until it passes or it gets the best of you.

So, bat die offs, culls, and their danger to humans.

Because of the health risks that bats can pose to humans, and pets as well, and the fact that flying foxes tend to live in large numbers and within close proximity to humans, bat culls are often carried out when numbers reach plague proportions, when there’s way too many bats.

So, hundreds of thousands of bats can be killed by councils around Australia when they become a serious danger or are causing damage to trees in botanical gardens.

When they’re not being killed by humans, they can suffer mass die offs because of extreme weather events in Australia such as heat waves. For instance, and as in that video at the start of this episode, in 2018 the heatwave in Sydney killed 100,000 bats in a weekend, a single weekend.

This is because they can’t sweat. They can’t really regulate their body temperature without flapping their wings or just finding shade. So, if the temperatures rise too much and for too long, bats can die.

So, what should you do if you see a bat? Don’t touch it. Okay? Seriously. Don’t touch bats, unless you’ve been vaccinated. Call your local wildlife hotline if you find one that’s in distress or in need of help. You can usually find those via a quick Google search.

And if for whatever reason you must handle the bat or move the bat, cover the bat with a towel or clothing and make sure you avoid skin contact with the bat. If you’re scratched or you’re bitten or even come into skin to skin contact with the bat, see a doctor immediately. Seriously. See a doctor.


Vocabulary:

A die-off – An event where many members of an organism die.

A health risk – an adverse event or negative health consequence due to a specific event, disease, or condition.

A local wildlife hotline – a phone number you can call for free to report injured animals to carers who can come and pick them up.

A series of arrivals – a number of instances where ST arrives SW one after the other.

Biologically inaccurate – imprecise in terms of biology.

Blind as a bat – unable to see; have very poor sight.

Bright pink – very vibrantly pink in colour.

By the time – when.

Carry ST out – do ST; complete an action.

Come into contact with ST – touch ST directly.

Due to ST – because of ST.

Extreme weather events – climatic conditions that are very severe or dangerous.

Feed on ST – of an organism to survive by eating a certain food.

Flu-like symptoms – a physical or mental feature which is regarded as indicating a condition of disease, particularly such a feature that is apparent to the patient similar to those of when you have a cold or the flu.

Get the best of SO – defeat SO; overcome SO.

Hence the name – thus why the name is what it is.

In and of themselves – with respect to its intrinsic or inherent nature without consideration of extraneous factors; per se, intrinsically.

In distress – be experiencing extreme anxiety, sorrow, or pain; be in trouble.

In need of help – requiring assistance.

In turnused to convey that an action, process, or situation is the result of a previous one.

Lethal to ST – deadly to ST.

Lose one’s life (to ST) – die (because of ST).

Man-made structures – things built by humans.

Navigate in complete darkness – be able to find one’s way around when there’s no light.

Of up to… – of as many as…

On a nightly basis – occurring every night.

On the other hand – in comparison.

Opt for ST – choose ST.

Prove to be ST – be shown to be the case.

Reach plague proportions – become so numerous as to be a hindrance.

Skin to skin contact -of one’s skin to touch the skin of ST or SO else.

Sustained flight – the ability to fly continuously.

Track ST down – find ST after looking for it.

Usually within a week or two – commonly occurring in less than 7-14 days.

Vacuum ST up – clean ST up or suck ST up in the way a vacuum does.

Within close proximity to ST – near ST.

You’ve got your… – used to denote someone or something that is familiar or typical of its kind.