The eastern grey kangaroo is one of Australia's most iconic animals and now new research has found they may develop and retain long term relationships with one another. A single group of kangaroos was tracked over a period of six years with researchers analysing more than 3000 photos.
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00:00 The mothers in our population actually became more social when they had joeys, which is
00:06 something that we looked at on an individual level, whereas previous studies, if you look
00:10 at it on a population level, it sort of looks like they're actually isolating themselves,
00:14 but we found they've just become a bit more social when they have joeys.
00:17 So more broadly, the overall findings from this report, what did you find and did anything
00:24 jump out at you and surprise you?
00:26 Well, I suppose the most surprising result was we found possible evidence for long term
00:30 relationships in eastern grey kangaroos, which I think is just something no one's found before.
00:35 And what is the impact of that?
00:37 I guess it just shows that the kangaroo relationships are so much more complex than people think.
00:41 People tend to really underestimate animal social relationships, especially with non-primates,
00:46 and I think it's just so interesting to be able to show that there's so much more going
00:49 on.
00:50 I thought it was really interesting because I have a lot of eastern greys around where
00:53 I live, and I thought they're so common.
00:56 Surely this had been studied before, but is it not an area that's looked into?
01:00 They have been studied a lot, but the difficulty is studying them individually and being able
01:05 to identify each kangaroo.
01:06 And then we also did a long term study, which took a long time.
01:10 So being able to see what each kangaroo was doing each year was just incredibly helpful.
01:13 Six years.
01:14 It's a long research project.
01:15 I was interested to read that they have what you call a fission and fusion social structure.
01:21 What is that and why is it important?
01:22 It's like when you see the kangaroos and they're moving constantly between groups.
01:26 They form these small groups within their populations and then they change them so frequently,
01:31 which I think is one of the reasons people didn't really think to look for long term
01:34 relationships in eastern grey kangaroos.
01:36 So are the males anti-social effectively?
01:39 They kind of do their own thing, is that right?
01:42 And how do they kind of change their relationships over time?
01:45 Males are an interesting one because they tend to leave their populations and then sometimes
01:49 come back years later, whereas females will stay in the same population.
01:52 And when males are in their populations, they'll sort of hop from group to group trying to
01:56 mate with various females.
01:57 So we did find most of these potential long term relationships amongst females and especially
02:02 females with young, so the mothers groups you were saying.
02:04 Yeah, yeah, that's great, isn't it?
02:06 So as someone who studies animals, what do you gain from a better understanding of the
02:11 social lives of eastern greys?
02:13 Well, I suppose on one level, if you're going to be, you know, kangaroos are such a unique
02:17 species to Australia and it's always important to be able to understand them.
02:21 And if you're going to be managing kangaroos in any capacity, it's important to know what
02:24 their different behaviours are going to be and how that's going to affect things like
02:28 breeding and dispersal.
02:30 But I just think it's also so important that we understand the species more because they're
02:33 one of our most iconic marsupials.
02:36 So how many kangaroos all up did you study?
02:38 And how do you go about this?
02:40 Because they're kind of hard to track.
02:41 They move over fairly large distances sometimes.
02:44 And they kind of look similar.
02:46 They look very, very similar.
02:47 I didn't want to say that.
02:48 They do, yes.
02:49 So we had a photographic survey.
02:51 So my supervisor from UNSW, Dr Terry Ord, went out a couple of days each year and took
02:56 photographs of every single kangaroo.
02:59 And we had about 3,500, which he then handed to me.
03:01 And I went through and I looked at them all to identify them.
03:04 And I did that with the shape of their ears, which is really unique to each kangaroo.
03:08 And it will remain consistent throughout the years.
03:11 And we had got 130 individual kangaroos over the six years.
03:15 Did you, I mean this might sound silly, but did you form any sort of affection or attachments
03:20 to any of these ones?
03:21 I did have favorites, yes.
03:22 Did you?
03:23 Yeah, we had a bit of a drought, which dropped the kangaroo population.
03:27 And then I remember the year after that when it started rising, some of the ones I hadn't
03:30 seen before came back.
03:31 And I was just pretty relieved to see them.
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