Interview: Phoebe tells us about cute native mice and sex-crazed marsupials

aussie, english, native, rats, phoebe, aussie english

In this interview episode of Aussie English I interview my good friend Phoebe who is a fellow PhD student at the museum with me. We both share the same supervisor, and like me Phoebe is studying some incredibly cute threatened native rodent species.

Interview: Phoebe tells us about cute native mice and sex-crazed marsupials

Pete: Alright. So attempt number two. We just tried to start this interview off but the battery died. So, once again I’m here with my friend Phoebe. Ah… she’s a fellow PhD student here at the museum. We have the same supervisor, both studying rats, and she recently got back from two weeks of fieldwork in the Grampians, in Australia, Victoria, in the western side of Victoria, and I thought I would do a mini interview with… with Phoebes together to tell you about her PhD project, um… a little bit about her fieldwork, and maybe a little bit about the Grampians as well. So, take it away Phoebes. Start again.

aussie, english, native, rats, phoebe, aussie englishPhoebe: Thanks Pete. So, I’m in the second year of my PhD and I work on two species of native Australian mice, and Australia has tons of native rodent species, um… many of which have already gone extinct and many more of which are endangered and at risk of extinction. So, I work on two of those species, the Smoky mouse and the New Holland mouse. Um… and they’re both really struggling in Victoria. So, the Smoky mouse, one of its remaining strongholds is the Grampians in western Victoria, and as Pete said I spent the last two weeks there um… trying to find Smoky Mice. So, I basically um… set up camp and lived in a tent there for two weeks in the pouring rain and crazy winds and spent my days hiking around, um… setting traps and checking traps and look for mice. So, when I find mice in my traps they’re actually like they don’t… they’re not your normal mouse traps. I’m not actually going out and killing all the threatened species. Um… I like… they’re little box traps, and they’ve got fluff and food in there, and the mice go in and sort of snuggle up for the night and I come round in the morning and take them out and weigh them and see whether it’s male or female, um… and take a little DNA sample and let them go again. And so, I do that every second month in the Grampians to see how the populations there are going, um… and to see why the populations fluctuate in different ways. So, why they go up and down. Um… and whether that’s related to things like rainfall or extreme weather events. Um, which is, yeah, part of my PhD.

Pete: So what have you found out so far with the data that you have collected over the last few years?

Phoebe: Well so far um… I’ve sort of confirmed that the species is really um… has a really localised distribution in the Grampians. So, a couple of years back I surveyed this entire mountain range in the Grampians, Victoria Range, and I found New Holland Mice [Smoky Mice*] within a tiny portion of that mountain range. So, they’re only in little populations in these really wet gulleys, um… along about 6-8km of the mountain range, which is quite a small area when you think about, like, the impact of fires and, like, the size of like potential fires when they sweep through and they impact the species and you might just lose the entire population of that species in that area if they’re… yeah, not able to cope with it.

Pete: And so, we actually had during your Masters degree when you were studying these guys a little more thoroughly, we had a massive bushfire go through the Grampians right?

Phoebe: Yeah.

Pete: And so, what did you find? So, you sampled them beforehand, didn’t you? And then the bushfire came through and you got to sample them again afterwards and you were afraid that they were going to have potentially have been wiped out, right?

Phoebe: Yeah, that was a real fear that we had because nobody had, like, seen um… Smoky mice go through that sort of fire before. So, we kind of assumed that they might actually get wiped out, um, and thankfully I went back after the fire and the fire had passed through all of the historical locations, um… within that mountain range.

Pete: And what had the fire done to the place?

Phoebe: It was just, it just… it was like a moon-scape, like it had obliterated all of the vegetation, like there was just nothing. There were burnt… burnt trees, like burnt tree trunks with no vegetation whatsoever and you just had rocky ground, and yeah, it was amazing, like… it was incredible that any species could actually persist in it because it just looked so inhospitable, like, there was nothing… nothing there. Um… so we went back into these sites and the only species that I did find in my traps was Smoky mice. So it actually survived in situ, so in place, like they’d stayed there through the fire, and they’ve continued to persist in the years following the fire in those sights. And there are other species coming back now too. So, you’ve got little antechinus, which are like tiny little marsupials, um… that run around and eat insects and…

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2012 before the bushfire.

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2012 after the bushfire.

 

 

 

 

 

 

 

Pete: So, they actually look like little rats but they’re actually more closely related to kangaroos, aren’t they, than they are rats?

Phoebe: Yeah, yeah, people always think that they’re like sort of a kind of mouse or something, but yeah they’re actually far more closely… like we’re more closely related to rats than these guys are, um… yeah, and they’re quite interesting, like, people always pick up on the fact that they um sort of shag themselves to death.

Pete: Do you want to explain a little bit about that? First of all, the word “shag” means to have sex everyone, just for those who didn’t know, or “to mate” in a more politically correct, scientific description.

Phoebe: So, um… male antechinus put all of their energy into reproducing. So, it comes to breeding season and they just pump all of their energy into producing testosterone and producing lots of sperm and running around trying to sleep with all of the female antechinus. Um… and…

Pete: Though they don’t really sleep do they?

Phoebe: They don’t seem to. Um… Yeah, so they just put everything into mating and then eventually their body condition deteriorates because they’re not putting any energy into like repairing their bodies anymore.

Pete: And they’re not eating, right?

Phoebe: They eat very little, um… and they… they do actually sleep very little, like you start catching them at the wrong time of day when they’d usually be asleep. So, they’re usually nocturnal and you’d only catch them, like, at night, um… but you start catching them in traps, um… actually during the daytime which is just, yeah, out of control.

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Dusky antechinus. Picture from Museum Victoria.

Pete: So, there’s these little… these tiny tiny little marsupials, probably Australia’s smallest marsupials, right? Or at least some of the smallest marsupials…

Phoebe: Some of the Smallest yeah…

Pete: Actually stop eating, the males stop eating and they stop worrying about anything aside from going out, searching for females, and having as much sex as possible over a period of what, it’s about two weeks isn’t it, where they… they all die because they…

Phoebe: Yeah, it’s a few weeks yeah…

Pete: …they all go out, mate themselves to death, don’t eat, don’t do anything else, and then all of a sudden you’re left with absolutely no males, right? Half the population disappears overnight effectively.

Phoebe: Yeah, so you’ve just got a lot of pregnant females, um… and there’s no males in the population at all until the females give birth. And they give birth to these tiny tiny pink little beans um… that grow into antechinus and they’re, sort of, they’ve got a very small pouch like all marsupials have got a little pouch, but theirs is more like a little little dint on their belly. And it just has these giant um… little babies start growing out of it until they’re nearly as big as their mum, and…

Pete: And they all hold on don’t they, to the underside of this antechinus?

Phoebe: Yeah, they all um… they latch onto the nipples or the teats and just stay there until they’re ready to go off and do their own thing. (Check this video out to see what it looks like.)

Pete: And so, we’re at that period right at the moment aren’t we, where you are catching a lot of antechinus but they’re all female and they all have babies, don’t they, at the moment, in their pouches slowly developing?

Phoebe: Um… so there’s two different species that I catch, um… one of them is [the] Dusky antechinus, and they’re at that stage where there’s no more males in the population and you’ve got these sort of jelly belly sized jelly bean babies like attached to their bellies, um… whereas Agile antechinus are still at the stage where the males are still in the population and they’ve got these massive, like, testes or um… and they’re just… you catch them all the time, and they just have very little um… regard for their own safety. Like, I had a couple of interesting um… experiences this last trip where I was checking the traps in the morning and it was pouring down with rain, so I was wearing a water proof jacket and I let go of an antechinus and instead of running away, which is what they should do and [what] they usually do, it ran up my jacket and sat there on my sleeve um… licking water off my jacket, and it was just like… it was absolutely adorable…

Pete: That’s so funny.

Phoebe: But it was like not the best survival behaviour for a species, ‘cause I’m this big potential predator.

Pete: I guess it’s a disadvantage, right, at that point if you’re more worried about your survival than about being active and going out looking for females to reproduce with you’re not going to pass on your genes as as… um… easily as ones that don’t care and just get out there and look for anything they can shag. Ah, cool. But back to the species that you were chasing, so you were catching smoky mice?

Phoebe: Yeah, yeah so, I caught a fair few smoky mice, um… well a reasonable amount for the species. I caught dozens more antechinus than I caught smoky mice but smoky mice tend to um… sort of persist in smaller numbers um… at times. And yeah, they’ve been fairly consistent in their numbers this year so far, so hopefully they’re doing alright and hopefully they’ll start breeding soon this um… this year as well.

Pete: And so, for those of… those listeners out there who probably cringe at the idea of studying rats, and just rats in general, how would you explain native Australian rodents compared to say the basic image most people will have when they think of a rat, which is the introduced pest species that you see eating out of bins and dumpsters in the city? What are the Smoky mice and other Australian rats like in comparison?

aussie, english, native, rats, phoebe, aussie englishPhoebe: They’re absolutely gorgeous, like, I’m slightly biased but Smoky mice in particular are, like, so soft and fluffy, and they’re this like beautiful blue-grey colour, and they’ve got like, you know, a little pink nose and little pink feet, and they’re just, like, adorable, like, they’re something that you’d look at and think of more as being a cute little, like, possum kind of thing rather than like a gross species of rat, um… and we’ve got so many species like that, like native rats and mice that are actually really really cute little fluffy things. I mean not that the, you know, be all and end all for a species, but yeah, they’re actually quite attractive little guys, and they don’t smell. Like they’ve got their own unique scents but they don’t smell disgusting like a house mouse or a black rat.

Pete: Yep. And so, you’re actually also studying another mouse species, another native rat species that’s a little smaller than the Smoky mouse. So, tell us a little bit about that.

Phoebe: Yeah, that’s the New Holland mouse are similarly endangered, um… throughout Victoria, um… and they’ve disappeared from different sites um… a lot over the past few years. So, they’re now known from only three of 10 locations across Victoria, um… and they’re… yeah, a bit smaller than Smoky mice but really quite adorable as well. Um… and I spend most of my time um… looking for them down at Wilson’s Promontory (Wilson’s Prom/The Prom), which is another beautiful national park here in Victoria. Um… and they live in totally different habitat, like, they have um… So, both species actually burrow and live underground in little burrow systems, um… but the New Holland mice tend to live in sandier soils, ‘cause they’re a bit smaller it probably makes it a bit easier for them to burrow through. Um… and yeah, they just run around eating grass and seeds and insects and fungi. Um… and also, just disappearing, which is what I’m trying to figure out, is why they’re disappearing but… yeah

Pete: And that was part of the reason you went to Wilson’s Prom, right? You had no records of them being there for a very long time, or at least they hadn’t been sampled by other scientists. And so, you went in to see if they were still there, and you were somewhat surprised when you found them, right?

Phoebe: Yeah, so New Holland mice used to be really abundant at Wilson’s Prom sort of in the mid 90’s, and then they sort of declined until the early 2000s, and then the last individual was seen there in 2010 um… where they literally just found one single individual. Um… and nobody saw any um… between then and when I started my work um… in 2015. Um… so, people had gone out looking for them, but they just… they couldn’t find them at any of these historic sites anymore. Um… so I went out and used camera traps, which are sort of like um… motion sensor activated cameras and heat-sensor activated cameras that take photos of the animals just doing their thing. Like, I’ll put out like a bait to lure them in and um… they go and investigate it and the camera takes lots of photos of them. Um… so I put those out across a huge chunk of the Prom, um… and found New Holland mice at 2 of my 50 sites. So, it was really exciting that I’d actually managed to find them. Um… [I’m] kind of disappointed that I found them at so few of the sites, but yeah, they’re still there just in really really low numbers.

Pete: So, what does that tell you about the species um… in general, I guess, and… how would you explain it, but… do they need large numbers and do they need to live… do they live, you know, across the entire landscape or are you more likely to find them in patches and in high numbers, low numbers? Can the species persist in low numbers dotted across the landscape? What do… are they like lights switching on and off too, the different populations? Or is this what you’re trying to find out to some degree?

Phoebe: Yeah, that’s one of the things I’m trying to find out, is how they are actually persisting. Um… at the moment it looks like there’s just this sort of one really small area where they’re persisting um… in quite decent numbers. Um… when I first trapped them there back in October the last year I only got three individuals which was devastating because that’s… like, I put in a lot of effort there and found three individuals and that is not enough to sustain a population. Um… but I kept trapping there and have been finding um… more um… sort of over Autumn this year. The numbers are starting to decline a bit again as we go through winter, but they’re still staying above like I’m down to about 12 individuals that I see per month um… at the Prom. Um… and yeah, it’s in this really localised area. So, one of the things at the Prom, um… is that there’s been all this um… native tea tree encroachment. So, tea tree is like a sort of shrubby tree species…

Pete: And it’s native to Australia, isn’t it, but not to that area?

Phoebe: Yeah, it’s native to Australia um… and it’s kind of native to that area but there’s been a lot of change in fire regimes and different grazing patterns. They used to have like sheep and cattle in the area. And it’s sort of just lead to this nightmare situation where the tea tree has just taken over the entire landscape, like they’re… it doesn’t allow any other plant species to persist. It’s just like this monoculture of tea tree, which means there’s just like the one species of tea tree um… across the whole landscape, and that just isn’t very good for supporting species like the New Holland mouse because they need, like, diversity in the plants um… that are present so that they have things to eat and so that the plants support different types of fungi and different types of insects for them to eat as well. Um… and yeah, that’s just sort of crept across most of the Prom, and the New Holland mice seem to be persisting in an area, um… in this one little patch where the tea tree hasn’t sunk its teeth in yet, so… yeah.

Pete: Ah cool, well hopefully they don’t suddenly disappear over night.

Phoebe: That would be my nightmare.

Pete: What are your expectations though? Do you think that they’ll… both with the Smoky mouse and the New Holland mouse, do you think that they’re both somewhat threatened but they’ve been in this state of being threatened by land regime changes and everything for a while now and they’re holding on, or are they on the decline, or on the increase?

Phoebe: I think Smoky mice are sort of holding on. Like, they’ve been put through a lot in terms of um… like introduced predators and landscape change. Um… but they seem to be hanging on in these little isolated populations, like, reasonably well. New Holland mice on the other hand are just dropping like flies. Like, I’m seriously concerned for the Wilson’s Prom populations um… because it seems to be so small and so isolated. The other two populations left in Victoria are doing much better um… but… I mean, the other seven that we’ve lost in the past couple of decades, like, it’s not look good, and we don’t entirely understand um… what’s happening with the species, which is yeah one of the reasons I’m studying it so that we can find out before it’s too late.

Pete: So, obviously it’s important too for the species themselves that you’re studying them, but I’m sure you get a lot of people saying, “Well what does it matter if we lose a mouse or a small rat like this?” and, “Why is this research that important? Why aren’t you more focused on things like the koala and kangaroo that are animals that matter?” You know, I’m sure you… I’m sure… What do you say to people who ask you those kinds of questions?

Phoebe: Yeah, I mean I understand that because people are much more attached to the animals that they see more readily, whereas these animals, like I see them all the time but most people would never get to see them because they don’t, like, run around in your field of vision, um… but yeah, the thing is all… all of these animals play different roles within ecosystems. So, whether it’s like distributing like different um… seeds or fungal spores to help other species to like, plant species or fungal species, to reproduce. Um… or like, these… some of these digging species like these mice they dig burrows and they like dig up um… like, fungi and stuff to eat, like, that really helps other species establish by a sort of um… disturbing the soil. So, it’s called like, bioturbation, where like um… species dig through the soil to get food and things, and that helps to aerate it and mix nutrients up and, like, makes a much healthier ecosystem where the plant species are able to um… like, get to the nutrients more easily, and like establish new sort of seedlings and that sort of thing. Like, ecosystems…

Pete: So, they’re all kind of relying on one another and if you take any one of those away it can become harder for any one of the individual species to survive.

Phoebe: Yeah, ecosystems are a big… Yeah, it’s like a big network where if you start knocking out species here and there the whole thing can collapse, and yeah… you end up with things like just, you know, solid tea tree for a couple of square kilometers, like…

Pete: So, by actually potentially putting in place things to protect not… not just this rat but this rat I guess to some degree, you’re actually going to end up protecting a lot of other things at the same time. So, it’s a bottom up kind of approach, is it?

Phoebe: Yeah, absolutely. Yeah, so like… for instance if we did predator control, so for like cats and foxes, um… to support New Holland mice, that’s also going to support a lot of other native species um… that are preyed upon by cats and foxes. So, like native birds and other small mammal species. Um… and it’s also going to yeah support the different vegetation communities by having the mice in there doing their thing mixing things up a bit.

Pete: Yep, so what do you think’s going to happen in the near future? And what do you think we need to do in order to save these kinds of species? What needs to be put in place in order to prevent them from permanently disappearing?

Phoebe: Um… we definitely need to study them more and understand what is causing different declines in different places, um… and then we need to act on it, like, put in predator control measures, or like habitat modification um… that sort of thing, like, we need to actually understand what’s going on and then just basically throw money at it. Like, it’s the only way that you can actually um… yeah… ensure that we’re going to save these species, and the current um… yeah… sort of, the current idea is to just be like, “Oh yeah, they’re declining, let’s just wait and see what happens.” And then it’s too late. And I mean we’ve already lost like, what, 30 Australian mammal species, um… in the last 200 years, and that’s like worse than like any other country has ever experienced, like, we’re number one in the world for wiping out mammal species. Um… yay! Go us! Um… yeah, like, it’s something that we need to take seriously and act on now because it’s going to be too late soon.

Pete: Awesome, ah that’s probably long enough for today. Thank you so much for sharing your insights Phoebes.

Phoebe: No worries. Thanks for chatting to me!

Pete: You’re welcome.

 

Check out Phoebe’s blog about studying native Australian rodents here.