What does a koala’s nose know? A bit about food, and a lot about making friends


Ben Moore, Western Sydney University and Edward Narayan, Western Sydney University

The koala’s nose is distinctive – it’s a big black leathery rectangle in the middle of a round, grey face that’s surprisingly soft to the touch. And every koala nose is unique.

A study of 108 wild koalas found distinctive patterns of pigmentation around the nostrils allowed observers on the ground to reliably recognise individual animals, even when they’re in the trees.




Read more:
A report claims koalas are ‘functionally extinct’ – but what does that mean?


But more importantly for the koala, the nose is an important connection between this iconic marsupial and the world it lives in, from sniffing out toxins to saying hello.

And it starts right at birth. The tiny newborn koala, despite weighing only half a gram, already has the ability to smell and feel its way towards the milky scent of the pouch and its mother’s teats.

A koala’s nose knows how to sniff out toxins

Koalas, famously, spend most of their time sleeping or resting. When they’re not sleeping or resting, they are mostly feeding or moving between trees. In both of these activities – or in other words, for most of their waking hours – they follow their nose.

Koalas nearly always smell their food carefully before eating. So many koala experts were surprised to learn recently that koalas don’t have particularly many genes for olfactory receptors – the receptors found on nerve cells in the nasal cavity for detecting different smells.




Read more:
Koalas sniff out juicy leaves and break down eucalypt toxins – it’s in their genome


This matches up with anatomical observations that also suggest that among marsupials, the koala’s sense of smell is probably relatively poor, partly as a result of features associated with conserving water.

Gum leaves are chock full of natural plant toxins and other unpleasant chemicals, and koalas choose trees that minimise their exposure to the worst of these.

But most of the toxins that influence koala feeding are not volatile – they have no smell. It falls to the koala’s sense of taste (and genes for taste receptors are especially abundant in the koala genome) to make a final decision on whether a leaf is safe to eat.

Fortunately for the koala, the only-slightly-toxic compounds called terpenes (the invigorating scent of Eucalyptus oil) are highly volatile and offer a useful cue to the levels of other toxins in a leaf.

And one advantage of being a specialist feeder with a basic diet, is that there are relatively few odour cues to learn. It’s also fortunate the leaves koalas are checking out are right in front of their noses!

The koala’s nose might not only smell plant toxins, it may also play a minor role in detoxifying them.




Read more:
A cull could help save koalas from chlamydia, if we allowed it


We know enzymes in our own noses can detoxify certain drugs, and in other specialist herbivores, such as woodrats, many of the same enzymes that detoxify natural plant toxins and drugs in the liver are also expressed in the lining of the nose.

These enzymes likely help stop the nose from becoming overwhelmed by odours and maintain sensitivity. Critically, they also protect the central nervous system, as nasal tissue is the only thing separating inhaled toxins from the brain.

A koala’s nose knows how to make friends

Sniffing out food is important, but it’s not the koala’s biggest forte. So why the big schnoz? The answer may lie with the importance of social communication.

Although the koala genome has relatively few olfactory receptors, it’s rich in vomeronasal receptors, which are expressed in cells in the nasal cavity that are sensitive to moisture-borne molecules like pheromones.

Koalas are generally solitary creatures, but that’s not to say they don’t know their neighbours. Along with the distinctive loud bellowing of male koalas during the breeding season, olfactory communication is what koalas use to find or avoid each other.

A male koala’s breeding season bellow. Video: Denise Dearing.

Koalas of both sexes often spend considerable time smelling the base and trunk of a tree before they decide whether to climb up or move on elsewhere. When they enter or leave a tree, koalas commonly dribble a stream of urine down the trunk, leaving a trail of chemicals that potentially reveal information about the koala’s sex, identity, dominance, relatedness to other koalas, readiness to mate, disease status and even what they’ve been eating.

But if koala urine is a book written in scent, the secretions of the male koala’s sternal gland are more like a barcode.

This gland is obvious as a yellow-brown stained patch of bare skin in the middle of male koalas’ chests, and offers a straightforward way to tell the sexes apart.

It secretes an oily mixture of fatty acids and other chemicals, which are then transformed into an even more complex chemical mixture by the unique bacterial community occupying each koala’s gland. The end result is a distinctive bouquet and an unmistakable badge of identity for each koala.

Nose kisses from a koala

Aside from these fascinating nasal abilities, there is one more thing that we love about the koala’s nose.

When wild koalas are brought into captivity, they continue to rely on their nose to learn about the strange new world around them – that includes their food and branches, but also the scientists and carers moving around them.




Read more:
Drop, bears: chronic stress and habitat loss are flooring koalas


They will pull anything of interest into smelling range, making them one of the few wild animals that will rub noses to say hello with humans and fellow koalas, even when barely acquainted!

But wild koalas are highly sensitive to human handling, which can generate sub-lethal stress through the stress hormone, cortisol.

Without question, the koala’s nose is fascinating and a marvel of evolution, but no matter how strong the temptation to touch it, please leave those koalas in peace!The Conversation

Ben Moore, Senior Lecturer in Ecology, Hawkesbury Institute for the Environment, Western Sydney University and Edward Narayan, Senior Lecturer in Animal Science, Western Sydney University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Advertisements

Dingoes and humans were once friends. Separating them could be why they attack



File 20190429 194630 g4xwba.jpg?ixlib=rb 1.1
Dingoes on K’Gari are the most genetically ‘pure’ in Australia.

Katie Woolaston, Queensland University of Technology

Two small children were hospitalised in recent weeks after being attacked by dingoes on K’gari (Fraser Island).

The latest attack involved a 14-month-old boy who was dragged from his family campervan by dingoes, an incident that could have ended with much more serious consequences than the injuries he sustained.

Fraser Island, famous for its wild dingo population, was renamed K’Gari in 2017. And the number of tourists involved in negative interactions with dingoes appears to be increasing.




Read more:
Why do dingoes attack people, and how can we prevent it?


The dingo, a wild dog of the Canis genus, were likely brought to Australia by Asian seafarers around 4,000 years ago.

Dingoes can be terrifying – but not when they’re puppies.
Shutterstock

While dingoes exist in many parts of Australia today, those on K’gari are thought to be “special” because of their genetic purity. This means they have not interbred with wild and domestic dogs to the same extent mainland dingoes have, and so are considered the purest bred dingoes in Australia.

They are legally protected because of this special status, and because they live in a national park and World Heritage Area. Unfortunately, it is precisely this protection and separation from humans that has driven much of the increase in interaction and aggression towards people.




Read more:
Like cats and dogs: dingoes can keep feral cats in check


This ongoing human-dingo conflict on K’Gari shows how our laws and management practices can actually increase negative encounters with wildlife when they don’t consider the history, ecology and social circumstances of the conflict area.

Law and policy ‘naturalised’ dingoes

The island’s laws and policies, such as the international World Heritage Convention and the more local Fraser Island Dingo Conservation and Risk Management Strategy, are focused on conserving a particular human idea of “natural wilderness”.

In practice, this means the management policy focuses on “naturalising” the dingo by effectively separating them from people and the sources of food they bring.

But dingoes, although wild animals, have never effectively been naturalised on K’Gari, so our attempts to maintain their “natural” and “wild” status is not entirely accurate.

K’Gari (Fraser Island) is the largest sand island in the world.
Shutterstock

Dingoes have a long history of being close with Aboriginal people. This human-dingo relationship continued as the island was used for mining and logging, as employees also lived with dingoes. They were fed by people, scavenged scraps from rubbish tips, and fed on leftover fish offal.

It is only in the last few decades we have sought to rewild dingoes by removing all forms of human-sourced food, separating them from human settlement.




Read more:
Living blanket, water diviner, wild pet: a cultural history of the dingo


Separating the animals from humans won’t work, however, when more than 400,000 tourists visit K’Gari every year, expecting to see a dingo.

International law and local management prioritise tourism, and a tourism-based economy is certainly preferable to the logging and sand-mining economies that existed before the national park was given World Heritage status in 1992.

Be dingo safe.
Shutterstock

But are such large visitor numbers in a relatively small space sustainable?

This question has been asked often, including by the Queensland government in their Great Sandy Region Management Plan.

Yet, there has been no serious consideration given to reducing tourist numbers or increasing fees, despite research suggesting visitors are willing to sacrifice some access for improved environmental outcomes and less crowding.

Such proposals have been specifically rejected by decision-makers within the Dingo Management Plan.




Read more:
Dingoes do bark: why most dingo facts you think you know are wrong


So where does that leave us?

We essentially have three options:

  1. if we wish to stick with the policy of dingo naturalisation and human separation, we must change our attitudes and values towards dingoes so people maintain an appropriate distance and do not inadvertently feed them. This can happen with education, fines and collaboration. While this is essentially what policies have attempted so far, there has been little effect on overall incident numbers

  2. we can take the naturalisation policy to its expected endpoint and completely separate tourists and dingoes. This may mean more fencing, greater fines and fewer annual visitors so rangers can educate and manage all visitors effectively

  3. we can drastically reevaluate how we value wildlife and how we place ourselves within the natural world. This would see an enormous overhaul of the regulatory framework, and would also require a deeper understanding of all the causes of conflict, other than just the immediate issue of tourism, habituation and feeding.

In practice, an effective dingo management policy would probably require a combination of all three options to maintain the pristine state of K’Gari, conserve the dingo population and improve human safety.The Conversation

Katie Woolaston, Lawyer, Queensland University of Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Goodies v baddies? Why labelling wild animals as ‘pests’ or ‘friends’ is holding farming back


Manu Saunders; Gary Luck; Rebecca Peisley, and Romina Rader, University of New England

It’s hard to keep wild animals out of farms. Birds, mammals and insects all affect crop yields, in positive ways (such as flies pollinating flowers) and negative ones (such as when birds damage fruit).

Agricultural research and management programs often deal with these interactions by focusing on simplistic “good” and “bad” labels: aphids are annoying pests, for example, whereas bees are little angels.

In reality, however, no animal is 100% a “goodie” or “baddie” – their effects on crop production vary with context. Interactions between animals and crops are influenced by seasons, landscapes, management practices, and other animals. They can also be affected by the social, cultural and economic values of the local farming community. The same species can be “good” in one system and “bad” in another.

It sounds complicated, because it is. But this is where ecological research can help. Understanding the interplay between these factors will help ensure that farms can protect wildlife while also providing us with food and other resources.

Good versus bad?

When we reviewed 281 papers that evaluated increases or reductions in crop yields due to wild birds or insects on farms, we found that the binary view of “good” and “bad” animals is still widespread.

Of the studies we looked at, 53% (mostly in the agricultural sciences) focused on identifying and managing the “baddies”, by weighing up costs that animals create for farmers by damaging crops. Another 38% (mostly ecology and conservation studies) calculated the impact of the “goodies”: benefits such as pollination and pest control. Only 9% of the studies we reviewed considered both costs and benefits in a single system.

This shows that most scientific studies are still taking an approach that is too simplistic. Attempting to link increases or reductions in crop yields with a single pest or helper species doesn’t usually tell the whole story. It doesn’t tell us about other factors that influence crop yields, like seasonal changes in animal activity, effects of different management practices, or interactions between different animal species.

Because so many studies have focused on quantifying the effect of one group of animals (such as bees), or focused on effects at one crop development stage (for example, using fruit set as an indicator of pollination efficiency), the overall body of knowledge on how wild animals affect crops has become disjointed and sometimes contradictory.

Moving forward

In a second paper, we suggest a new way to address these complex issues that considers the social and environmental contexts of crop production across the entire growing season. By looking at the interplay between the various positive and negative effects, we can gain a more realistic estimate of how crop yields are affected by wild animals.

Here’s an example. In Australian almond orchards, native birds are often considered pests because they can cause crop losses by pecking at developing fruit. But after harvest has finished, the same birds also remove the decaying “mummy” nuts left on trees. Growers sometimes use paid manual labour to remove these nuts, because they harbour disease and pests that can damage the trees.

A cost-benefit analysis of shows that the positive economic value of the birds cleaning up the mummy nuts outweighs the cost of crop losses from damaged almonds. Averaged across the entire plantation, the presence of the birds is a net positive for farmers. This means that letting birds do their thing could be more cost-effective for growers than deterring the birds and then paying people to remove the mummy nuts. But without this cost-benefit approach, it easy to imagine how farmers would persist in viewing the birds as crop pests and shooing them away.

Very few studies have considered how wild animals create this type of cost-benefit trade-off in farming ecosystems. Yet this approach is central to the study of ecology, and there are obvious parallels between natural and agricultural systems. Both, for instance, have pollination and pest control as key functions.

Farms are ecosystems too. So we need to find a way to maintain sustainable crop production while also protecting biodiversity and ecosystem function. Doing this means moving beyond simplified systems and intensive production.

Productive farms have complex cycles of interactions between crops, wild animals and people. These cycles need to be sustained, not isolated from the system. As with any ecosystem, understanding is the first step towards protection.

The Conversation

Manu Saunders, Post-doctoral Research Fellow (Ecology); Gary Luck, Professor in Ecology and Interdisciplinary Science; Rebecca Peisley, PhD Candidate, Institute for Land, Water and Society, and Romina Rader, Lecturer in Community Ecology, University of New England

This article was originally published on The Conversation. Read the original article.

Showcase Your Travel Photos


One of the joys I have following a holiday, having travelled to some wild place within Australia, is to share those photos with others. Many years ago that would be primarily with family and friends, but now with the advent of the World Wide Web I am able to share these photos with a much wider audience. I tend to post my photos all over the place, though I have to confess I am way behind where I would like to be in this regard. I have a lot of work to do and hopefully I can make some useful progress on this front in the weeks to come – especially as I recover from upcoming surgery.

The link below is to an article that looks at 5 ways Bloggers can use their photos to enhance their content.

For more visit:
http://blog.travelworldpassport.com/use-your-pictures-create-visual-content-strategy/

Spontaneous Travel


The idea of spontaneous travel has always been something I have loved, even though I’m probably one of the worst exponents of it. When I was younger I used to like getting a group of friends together and heading off into the Great Outdoors, of which there was plenty in New South Wales, Australia – even in our region around Newcastle. Many great times were had travelling around the Barrington Tops, Watagans and the Central Coast. Now though the whole idea of spontaneous travel seems almost to difficult to materialise. However, in recent times the dream of spontaneous travel has returned and I have real intentions of realising it.

The link below is to an article that takes a look at spontaneous travel and gives 9 ways you can bring it about.

For more visit:
http://blog.travelworldpassport.com/be-more-spontaneous-travel-often/

If you want to help the environment, try not being a jerk to your friends


Grist

We’ve heard all the complaints: We green-minded people are annoying. We’re self-righteous. We nag. We judge. And we don’t always practice what we preach.

But — not to sound like a broken record — there are some serious, civilization-threatening problems that we’re trying to tackle here. So what’s the best way to get other people on board with acting sustainably? Via Pacific Standard, here is a research-backed tip: Act nicely, and don’t make people feel like hypocrites.

In this study, researchers hung out in a supermarket and approached shoppers in one of three ways: letting them be; asking them to sign a poster that said “Stop using plastic bags. If I can do it, so can you”; or asking them to sign the poster and then “remember past transgressions” — i.e. not-so-green choices. The researchers called this last bit the “hypocrisy condition.”

View original post 141 more words

Guppies: Hangouts with Ugly Friends


The link below is to an article about Guppies and their ugly friends. Perhaps I can take a few tips from them (lol).

For more visit:
http://www.australiangeographic.com.au/journal/guppies-hang-with-ugly-friends-to-appear-more-attractive.htm