How to: trap fussy marsupials (i.e. Antechinus)

Before you start work on a new species, it's generally accepted practice to read every single piece of literature about them that you can get your hands on, talk to anyone you can find who's worked on them before, and generally scrutinise every little thing that could go wrong and plan for it all.

They may look painfully cute, but at the risk of anthropomorphising, I think Antechinus are actually pretty devious. Image credit: Amanda Niehaus.

Unfortunately, I discovered that no matter how much you read about them, animals are always going to throw curve-balls at you - and in the end, nothing can beat actually getting stuck in and obtaining some hands-on experience, because everyone has different experiences and each species has their own little foibles. Regardless, I decided to write this little "how to" for others venturing into the world of Antechinus trapping. Some of my experiences might prove useful - and hopefully help minimise the amount of time you spend figuring out what the hell you're doing!

Sit back, relax, and remember the most important thing when working on a new species: try to stay calm. Image credit: Amanda Niehaus.

This year, my biggest task was establishing a breeding population of animals so that I actually have something to work on for the rest of my PhD. The very first step in this mission was to catch some animals in order to start up a study population. So, Amanda and I did some research to find out where our beautiful little target species lives, what habitat it prefers, where a large population is located, how other people have trapped them - we did all the paperwork and got all the permits, and then we set out - excited, expecting a few bumps in the road, but overall feeling pretty confident.

Each of our stainless steel Elliot traps was waterproofed using a plastic bag tied around the back end of the trap (we started off using large freezer bags, but once we realised how many we were going through we switched to biodegradable bags). Waterproofing is awesome for the animals inside the trap, but it is essential that you place the trap so that the entrance is lower than the back of the trap so that any water that does get in can drain out. We also put a handful of synthetic fluff from the inside of a pillow at the back of the trap, behind the bait, as bedding so the animal could stay warm overnight. Image credit: Amanda Niehaus. 

And then... we didn't catch anything. Not even a single bush rat. So, of course, we did some trouble-shooting. Were we trapping in the wrong type of habitat? "Open sclerophyll with a complex understory" might sound specific, but - as we discovered - when you apply it out in nature, it describes quite a variety of habitats.

Different types of open sclerophyll forest with a complex understory, none of which produced any Antechinus. Image credit: Amanda Niehaus.

We tried trapping a couple of nights in all of them without success. Then, on a whim, we decided to try out a little section of rainforest we had stumbled upon a few days earlier. Jackpot! First Antechinus, and about a bazillion bush rats.

Animals we trapped: Melomys, Antechinus, and the abundant bush rat. Image credit: Amanda Niehaus.

Even though we had found a population, our trap rate was still a little low. We also noticed that the Antechinus weren't really eating our standard bait mix of peanut butter and oats, which made sense given their primarily insectivorous diet. From our discussions with other researchers who had successfully kept Antechinus in captivity, we knew that they would eat most kinds of meat as long as they weren't too tough or stringy. So, we decided to experiment with different baits. We tried beef mince, chicken hearts, ox kidneys (which I don't recommend as their smell permeates everything), lamb hearts, kangaroo mince, liver... even roast chicken. However, we found that the optimal bait that both attracted the Antechinus and got eaten was beef mince mixed with peanut butter and oats.

The optimal bait: mince, peanut butter and oats. Tasty!

In addition to the bait, we also followed some advice we were given from my co-supervisor, Dr Diana Fisher, and used Antechinus-scented bedding in the trap. This completely outdid any sort of bait in terms of attracting Antechinus to the traps. We'd make up a big bag of scented fluff by placing a bunch of soiled bedding from the animals we had already caught in with a big bag of synthetic pillow fluff and leaving it out in the sun for a few hours, and voila - stinky Antechinus fluff! This worked wonders for trapping; because we were out there during the breeding season, male Antechinus were attracted to female-scented fluff, and females were attracted to male-scented fluff. Pretty cool, hey?

One of our little ladies with - yup - pouch babies! Like tiny little pink jelly beans. Image credit: Amanda Niehaus.

So, we managed to trap our animals. We didn't get as many as we'd hoped for, but it was a great start. And Antechinus, while being fussy and awkward, are also intelligent, personable, and frankly kind of a delight to work on - at least when they're not outsmarting you. I'm getting the feeling that I'll be writing a few more "how to"s before my PhD is up!

Antechinus trapping is fun - and check out the habitat we did get our Antechinus from. Image credit: Amanda Niehaus.

All images by Rebecca Wheatley unless otherwise credited.

How to: avoid tiny zippy animal escape

 Over the course of various research endeavours, I've worked on a wide variety of animals, ranging all the way from invertebrate larvae to tennis players. However, my biggest research projects have definitely been my Honours and my PhD, which I did/am doing on the Asian house gecko (Hemidactylus frenatus) and the yellow-footed Antechinus (Antechinus flavipes), respectively.

What do these two animals, a reptile and a small carnivorous marsupial, have in common? 

Asian house gecko vs. yellow-footed Antechinus. Image credit: Amanda Niehaus, Rebecca Wheatley.

Well, they're both pretty small. And they're also both pretty dang fast.

Cute little rascals. Image credit: Wikimedia Commons, Rebecca Wheatley.

These two factors create a high-stress environment when handling the animals is unavoidable but you can't quite handle the thought of them escaping. You can believe me when I say that handling tiny, zippy animals develops you some pretty epic reflexes – but, regardless of how good you get, sometimes you're bound to slip up and one will get away. Rather than spend half an hour crawling around the lab floor and occasionally smashing your head off low-hanging shelves, wouldn't it be good to have a way to handle them such that a dashing escape resulted in them not going anywhere?

Image credit: Rebecca Wheatley (left/right), Amanda Niehaus (middle).

This is where mums are great. I was lamenting over gecko escape (especially painful to recapture because they're prone to caudal autotomy, or tail-dropping), and my mum came up with a genius idea that's proven just as useful for Antechinus handling.

Luckily neither species minds a firm grip.

Step 1: Go buy a delicates bag from your local grocery store. Hell, buy a pack of three different sized ones for AUD$3.

Step 2: Put your animal's little hut in the bag.

Step 3: Put your arm in the bag, and zip it or draw-tie it up around your arm as depicted below.

Ratbags aren't escaping now! Image credit: Amanda Niehaus.

Step 4: Get the little brat out and do whatever you need with it. If it tries the great escape, guess what? It ain't getting out of the bag and is easy to recapture.

Various things you can do with the animals once they're in the bag - even if it's just getting a good grip so you can move it to something else.

So there you have it: a cheap, easy way to avoid tiny, zippy animal escape. Thanks mum! Here's to that genius gene transmission, right?

All images by Rebecca Wheatley unless otherwise credited.

A collection of sex-crazed maniacs

The time has come. The paperwork has been done; the preparations have been made. That's right: it's time to go get some study animals. Over the course of the next few months, our post-doc Amanda Niehaus and I (along with some fantastic volunteers) are starting to collect the animals my PhD will use, the yellow-footed Antechinus, Antechinus flavipes.

What a cutie. Image credit: Storm Martin.

If you don't know what an antechinus is, that's cool (you can see what they look like in the picture above) - they are fairly obscure animals that aren't all that well known even amongst the Aussies that share their habitat. Although they look like exceptionally pointy-faced mice, antechinus aren't rodents; they are members of the Dasyuridae, a family of small, carnivorous (usually insectivorous) marsupials. Some slightly better-known dasyurids include quolls and Tasmanian devils.

Unlike quolls and Tassie devils, antechinus are pretty tiny. Image credit: Storm Martin.

The antechinus' biggest claim to fame revolves around its wacky reproductive cycle. Unlike most mammals, antechinus are semelparous. That means that they invest all of their energy into one reproductive cycle and die shortly afterwards (unlike most other mammals, which are iteroparous, meaning that they reproduce multiple times throughout their life). The wacky component of all of this is that once the males reach reproductive maturity, they stop producing sperm; thus begins a frantic race to mate as many times as possible and spread their genes as far as they can before they die. Everything else gets shut down, and they literally breed until their bodies disintegrate. Sound extreme? Recent research has discovered that the reason for this frantically suicidal mating is probably due to intense sperm competition. In fact, both male and female antechinus are pretty friendly and like to cuddle up together at night, so there's actually little to no fighting going on at all. This makes them an awesome animal to work on, as their short life-cycle means that you can do multigenerational studies quite easily (and you can house them together).

Although they love to cuddle each other, antechinus aren't quite so fond of human handlers.

Although I'm still working out the specifics, my PhD is examining the effect of habitat structural complexity on performance, behaviour and overall fitness. Amongst other things, I'm looking at the effect the habitat complexity during development has on motor control and cognitive function in adults – for example, does exposure to a more complex habitat improve an animal's coordination as an adult? Does it improve its problem-solving abilities? These sorts of questions have applications well outside of the marsupial realm, so my results could be applicable to many other species. We're planning on establishing a breeding colony of semi-wild antechinus that we can raise in large, nature-simulating microcosms in order to investigate these questions.

Sunset at the Great Sandy National Park.

To collect our little darlings, we are travelling up north to the Great Sandy National Park near Cooloola, close to where a study by Geoffrey C. Smith identified a plentiful population back in 1984. Our first trapping trip took place last month, and while it took us a while to hit the right habitat (while it might sound specific, it turns out that "open sclerophyll with a complex understory" can actually apply to a wide range of habitats), we eventually managed to collect 12 antechinus of mixed sex.

Kuna, one of our little females. Image credit: Amanda Niehaus.

We caught other animals as well, including a few species of native rats. The bush rat, Rattus fuscipes, made frequent appearances and graced us with its delightful trap etiquette almost every day; any self-respecting rodent should know that the only acceptable way to behave when trapped in a small space with no way out is to defecate thoroughly and plentifully over every surface available. Anything else is pure barbarism. 

Despite their horrific smell, Rattus fuscipes are pretty dang cute.

We have at least a few more trips ahead of us before we'll have enough to start a breeding program to get our first set of babies to raise in controlled environments. Here's to hoping that this is the start of a beautiful (and productive!) friendship.

Smart, friendly (mostly) and completely adorable, not to mention sex lives that provide amazing party conversation fodder. Did I score? Heck yes! Image credit: Storm Martin.

All images by Rebecca Wheatley unless otherwise credited.