0:00:00.557,0:00:03.065 (comical synthesized music) 0:00:03.065,0:00:06.483 NARRATOR: They're extremely awkward on land... 0:00:09.102,0:00:11.367 And not exactly graceful in the water. 0:00:13.142,0:00:16.851 But there's something endearing about these egg-laying mammals. 0:00:17.415,0:00:20.621 Platypuses can only be found in the rivers, streams, and lakes 0:00:20.621,0:00:23.682 along the East Coast of Australia. 0:00:25.092,0:00:28.729 But they range as far North as Northern Queensland, all the way down 0:00:28.729,0:00:31.186 to the Southern island of Tasmania. 0:00:32.090,0:00:34.601 That's quite a range for these little creatures. 0:00:34.601,0:00:36.937 But there are gaps between populations. 0:00:36.937,0:00:39.799 Large tracts of land between the rivers and lakes 0:00:39.799,0:00:44.284 make it difficult for the platypuses to migrate from one area to another. 0:00:45.512,0:00:47.183 Researchers believe it's possible 0:00:47.183,0:00:50.851 that isolated pockets of animals could have evolved differently, 0:00:50.851,0:00:53.708 could even be separate subspecies. 0:00:54.555,0:00:59.118 The interesting things about platypus are that, as you come up the coast from Tasmania, 0:00:59.118,0:01:01.528 they get smaller. 0:01:01.528,0:01:05.999 As well as that, their body size is actually less in some of the Northern ones, 0:01:05.999,0:01:08.360 so the maximum weight for one in this area 0:01:08.360,0:01:12.957 is somewhere in the region of a kilogram, about two and a half pounds. 0:01:12.957,0:01:17.444 Whereas they're around about three times that weight in Tasmania. 0:01:17.444,0:01:20.614 NARRATOR: Stephen Kolomyjec from James Cook University 0:01:20.614,0:01:25.960 is using genetic material to determine gene flow from one population to another. 0:01:25.960,0:01:27.818 He examines the size and health 0:01:27.818,0:01:30.419 of populations as well. 0:01:30.419,0:01:36.230 What fascinates him the most are the differences between the Northern and Southern platypuses. 0:01:36.230,0:01:39.666 The platypuses up here in North Queensland are about a third of the size of the ones down South, 0:01:39.666,0:01:42.493 which is a pretty big size difference. 0:01:42.493,0:01:45.604 It may be because of climate, but it may be because of actual differences 0:01:45.604,0:01:47.708 in the species itself. 0:01:47.708,0:01:51.131 BLAIR: Populations here are isolated from the populations in the South, 0:01:51.131,0:01:54.753 so we're interested in looking at the effects of the gaps in the range, 0:01:54.753,0:01:59.119 and especially this far North, and one of the tools that we're using to do that 0:01:59.119,0:02:01.982 is population genetics. 0:02:05.666,0:02:09.029 NARRATOR: Stephen and his colleague David Blair are working in some of the oldest 0:02:09.029,0:02:11.796 rainforest in the world. 0:02:11.796,0:02:13.100 KOLOMYJEC: This is Dirran Creek. 0:02:13.100,0:02:17.337 It's a tributary of the North Johnstone River Catchment. 0:02:17.337,0:02:21.475 It's one of the many Upland freshwater streams in North Queensland, 0:02:21.475,0:02:24.311 and it's abundant in platypuses. 0:02:24.311,0:02:28.468 NARRATOR: Collecting genetic samples from a platypus can be rather challenging. 0:02:28.468,0:02:31.618 Special nets are carefully placed in the streams. 0:02:31.618,0:02:35.434 They're not weighted down, so platypuses can swim up to the surface 0:02:35.434,0:02:39.382 once they become entangled, to prevent drowning. 0:02:39.382,0:02:43.297 With the nets in place, the team awaits until nightfall, when platypuses 0:02:43.297,0:02:45.605 are more active. 0:02:45.605,0:02:48.532 Then it's time to collect their subjects. 0:02:49.570,0:02:56.543 Here's something most people might not be aware of: A platypus should always be held by its tail. 0:02:56.543,0:02:58.933 Especially if it's a male. 0:02:58.933,0:03:03.716 They're one of the few venomous mammals, with a spur on the hind foot 0:03:03.716,0:03:06.317 capable of injecting some rather potent 0:03:06.317,0:03:08.592 and painful venom. 0:03:08.592,0:03:14.119 So gripping the fatty tail is best for the platypus and the handler. 0:03:14.119,0:03:17.230 Now it's time to collect the necessary data. 0:03:17.230,0:03:18.999 The platypus is weighed... 0:03:18.999,0:03:19.600 KOLOMYJEC: 200. 0:03:19.600,0:03:21.503 NARRATOR: And measured, both the body... 0:03:21.503,0:03:22.246 KOLOMYJEC: 43. 0:03:22.246,0:03:23.871 NARRATOR: And the sizable bill. 0:03:23.871,0:03:25.032 KOLOMYJEC: 53. 0:03:25.032,0:03:28.794 NARRATOR: The scientists extract samples of DNA. 0:03:28.794,0:03:31.905 BLAIR: The principal samples that we're collecting for that is a small piece of skin 0:03:31.905,0:03:35.415 from the toe web on the edge of the foot. 0:03:35.415,0:03:39.486 That gives us enough DNA, when we take that back to the laboratory, 0:03:39.486,0:03:42.819 to be able to do quite a lot of genetic analysis. 0:03:42.819,0:03:47.928 In addition to that, we're collecting a little bit of toe skin to go to a laboratory in Adelaide, 0:03:47.928,0:03:52.866 where researchers are making cell cultures, for further genetic work. 0:03:52.866,0:03:54.601 They're interested in chromosome studies. 0:03:54.601,0:04:00.140 They're interested in studies on the rather strange sex chromosomes that platypus have. 0:04:00.140,0:04:05.379 Well, most mammals have an XY sex-determining system. 0:04:05.379,0:04:09.568 Well, the platypus has gone rather a long way further than that. 0:04:09.568,0:04:13.754 The platypus has five X chromosomes and five Y chromosomes. 0:04:13.754,0:04:16.190 You can ask the question "Why?" 0:04:16.190,0:04:18.392 I can't give you an answer. 0:04:18.392,0:04:20.460 NARRATOR: Once the platypus is microchipped... 0:04:20.460,0:04:21.094 KOLOMYJEC: There we go. 0:04:21.094,0:04:24.198 NARRATOR: It's released back into the water. 0:04:24.198,0:04:26.233 KOLOMYJEC: Just let him go gently. 0:04:26.233,0:04:29.119 We hope to learn how much difference there is between Northern populations 0:04:29.119,0:04:30.838 from Southern populations. 0:04:30.838,0:04:33.740 Up here in the North, there are a few gaps where they just do not occur. 0:04:33.740,0:04:36.510 And there are no historical records of them ever occurring in those areas. 0:04:36.510,0:04:41.448 And so we're looking at what kind of effect these gaps have had on their genetic health. 0:04:41.448,0:04:44.816 The actual species -- they might be very different, they might not be different. 0:04:44.816,0:04:50.395 It depends on when the last platypus was able to cross these gaps. 0:04:51.491,0:04:54.461 NARRATOR: If the smaller Northern platypuses are found to be genetically different 0:04:54.461,0:05:00.200 from the Southern platypuses, they may be recognized as a newly identified subspecies, 0:05:00.200,0:05:07.444 making them an even more unique version of one of the most unique animals on the planet. 0:05:11.380,0:05:14.314 ANNOUNCER: Sponsored by National Geographic Mission Programs, 0:05:14.314,0:05:17.050 taking science and exploration 0:05:17.050,9:59:59.000 into the new millennium.