WEBVTT 00:00:00.557 --> 00:00:03.065 (comical synthesized music) 00:00:03.065 --> 00:00:06.483 NARRATOR: They're extremely awkward on land... 00:00:09.102 --> 00:00:11.367 And not exactly graceful in the water. 00:00:13.142 --> 00:00:16.851 But there's something endearing about these egg-laying mammals. 00:00:17.415 --> 00:00:20.621 Platypuses can only be found in the rivers, streams, and lakes 00:00:20.621 --> 00:00:23.682 along the East Coast of Australia. 00:00:25.092 --> 00:00:28.729 But they range as far North as Northern Queensland, all the way down 00:00:28.729 --> 00:00:31.186 to the Southern island of Tasmania. 00:00:32.090 --> 00:00:34.601 That's quite a range for these little creatures. 00:00:34.601 --> 00:00:36.937 But there are gaps between populations. 00:00:36.937 --> 00:00:39.799 Large tracts of land between the rivers and lakes 00:00:39.799 --> 00:00:44.284 make it difficult for the platypuses to migrate from one area to another. 00:00:45.512 --> 00:00:47.183 Researchers believe it's possible 00:00:47.183 --> 00:00:50.851 that isolated pockets of animals could have evolved differently, 00:00:50.851 --> 00:00:53.708 could even be separate subspecies. 00:00:54.555 --> 00:00:59.118 The interesting things about platypus are that, as you come up the coast from Tasmania, 00:00:59.118 --> 00:01:01.528 they get smaller. 00:01:01.528 --> 00:01:05.999 As well as that, their body size is actually less in some of the Northern ones, 00:01:05.999 --> 00:01:08.360 so the maximum weight for one in this area 00:01:08.360 --> 00:01:12.957 is somewhere in the region of a kilogram, about two and a half pounds. 00:01:12.957 --> 00:01:17.444 Whereas they're around about three times that weight in Tasmania. 00:01:17.444 --> 00:01:20.614 NARRATOR: Stephen Kolomyjec from James Cook University 00:01:20.614 --> 00:01:25.960 is using genetic material to determine gene flow from one population to another. 00:01:25.960 --> 00:01:27.818 He examines the size and health 00:01:27.818 --> 00:01:30.419 of populations as well. 00:01:30.419 --> 00:01:36.230 What fascinates him the most are the differences between the Northern and Southern platypuses. 00:01:36.230 --> 00:01:39.666 The platypuses up here in North Queensland are about a third of the size of the ones down South, 00:01:39.666 --> 00:01:42.493 which is a pretty big size difference. 00:01:42.493 --> 00:01:45.604 It may be because of climate, but it may be because of actual differences 00:01:45.604 --> 00:01:47.708 in the species itself. 00:01:47.708 --> 00:01:51.131 BLAIR: Populations here are isolated from the populations in the South, 00:01:51.131 --> 00:01:54.753 so we're interested in looking at the effects of the gaps in the range, 00:01:54.753 --> 00:01:59.119 and especially this far North, and one of the tools that we're using to do that 00:01:59.119 --> 00:02:01.982 is population genetics. 00:02:05.666 --> 00:02:09.029 NARRATOR: Stephen and his colleague David Blair are working in some of the oldest 00:02:09.029 --> 00:02:11.796 rainforest in the world. 00:02:11.796 --> 00:02:13.100 KOLOMYJEC: This is Dirran Creek. 00:02:13.100 --> 00:02:17.337 It's a tributary of the North Johnstone River Catchment. 00:02:17.337 --> 00:02:21.475 It's one of the many Upland freshwater streams in North Queensland, 00:02:21.475 --> 00:02:24.311 and it's abundant in platypuses. 00:02:24.311 --> 00:02:28.468 NARRATOR: Collecting genetic samples from a platypus can be rather challenging. 00:02:28.468 --> 00:02:31.618 Special nets are carefully placed in the streams. 00:02:31.618 --> 00:02:35.434 They're not weighted down, so platypuses can swim up to the surface 00:02:35.434 --> 00:02:39.382 once they become entangled, to prevent drowning. 00:02:39.382 --> 00:02:43.297 With the nets in place, the team awaits until nightfall, when platypuses 00:02:43.297 --> 00:02:45.605 are more active. 00:02:45.605 --> 00:02:48.532 Then it's time to collect their subjects. 00:02:49.570 --> 00:02:56.543 Here's something most people might not be aware of: A platypus should always be held by its tail. 00:02:56.543 --> 00:02:58.933 Especially if it's a male. 00:02:58.933 --> 00:03:03.716 They're one of the few venomous mammals, with a spur on the hind foot 00:03:03.716 --> 00:03:06.317 capable of injecting some rather potent 00:03:06.317 --> 00:03:08.592 and painful venom. 00:03:08.592 --> 00:03:14.119 So gripping the fatty tail is best for the platypus and the handler. 00:03:14.119 --> 00:03:17.230 Now it's time to collect the necessary data. 00:03:17.230 --> 00:03:18.999 The platypus is weighed... 00:03:18.999 --> 00:03:19.600 KOLOMYJEC: 200. 00:03:19.600 --> 00:03:21.503 NARRATOR: And measured, both the body... 00:03:21.503 --> 00:03:22.246 KOLOMYJEC: 43. 00:03:22.246 --> 00:03:23.871 NARRATOR: And the sizable bill. 00:03:23.871 --> 00:03:25.032 KOLOMYJEC: 53. 00:03:25.032 --> 00:03:28.794 NARRATOR: The scientists extract samples of DNA. 00:03:28.794 --> 00:03:31.905 BLAIR: The principal samples that we're collecting for that is a small piece of skin 00:03:31.905 --> 00:03:35.415 from the toe web on the edge of the foot. 00:03:35.415 --> 00:03:39.486 That gives us enough DNA, when we take that back to the laboratory, 00:03:39.486 --> 00:03:42.819 to be able to do quite a lot of genetic analysis. 00:03:42.819 --> 00:03:47.928 In addition to that, we're collecting a little bit of toe skin to go to a laboratory in Adelaide, 00:03:47.928 --> 00:03:52.866 where researchers are making cell cultures, for further genetic work. 00:03:52.866 --> 00:03:54.601 They're interested in chromosome studies. 00:03:54.601 --> 00:04:00.140 They're interested in studies on the rather strange sex chromosomes that platypus have. 00:04:00.140 --> 00:04:05.379 Well, most mammals have an XY sex-determining system. 00:04:05.379 --> 00:04:09.568 Well, the platypus has gone rather a long way further than that. 00:04:09.568 --> 00:04:13.754 The platypus has five X chromosomes and five Y chromosomes. 00:04:13.754 --> 00:04:16.190 You can ask the question "Why?" 00:04:16.190 --> 00:04:18.392 I can't give you an answer. 00:04:18.392 --> 00:04:20.460 NARRATOR: Once the platypus is microchipped... 00:04:20.460 --> 00:04:21.094 KOLOMYJEC: There we go. 00:04:21.094 --> 00:04:24.198 NARRATOR: It's released back into the water. 00:04:24.198 --> 00:04:26.233 KOLOMYJEC: Just let him go gently. 00:04:26.233 --> 00:04:29.119 We hope to learn how much difference there is between Northern populations 00:04:29.119 --> 00:04:30.838 from Southern populations. 00:04:30.838 --> 00:04:33.740 Up here in the North, there are a few gaps where they just do not occur. 00:04:33.740 --> 00:04:36.510 And there are no historical records of them ever occurring in those areas. 00:04:36.510 --> 00:04:41.448 And so we're looking at what kind of effect these gaps have had on their genetic health. 00:04:41.448 --> 00:04:44.816 The actual species -- they might be very different, they might not be different. 00:04:44.816 --> 00:04:50.395 It depends on when the last platypus was able to cross these gaps. 00:04:51.491 --> 00:04:54.461 NARRATOR: If the smaller Northern platypuses are found to be genetically different 00:04:54.461 --> 00:05:00.200 from the Southern platypuses, they may be recognized as a newly identified subspecies, 00:05:00.200 --> 00:05:07.444 making them an even more unique version of one of the most unique animals on the planet. 00:05:11.380 --> 00:05:14.314 ANNOUNCER: Sponsored by National Geographic Mission Programs, 00:05:14.314 --> 00:05:17.050 taking science and exploration 00:05:17.050 --> 99:59:59.999 into the new millennium.