1 00:00:01,180 --> 00:00:04,780 This cricket is about to be dinner. 2 00:00:04,780 --> 00:00:07,500 New research reveals what makes a frog's tongue 3 00:00:07,500 --> 00:00:09,920 such a formidable weapon. 4 00:00:09,920 --> 00:00:13,000 This is Scientific American. I'm Lydia Chain. 5 00:00:13,000 --> 00:00:14,719 Since the entire attack takes less 6 00:00:14,719 --> 00:00:16,190 than a tenth of a second 7 00:00:16,190 --> 00:00:17,420 the researchers set up high-speed 8 00:00:17,420 --> 00:00:19,820 cameras to capture the action. 9 00:00:19,820 --> 00:00:22,280 "Literally in the blink of an eye, the insect is gone 10 00:00:22,280 --> 00:00:24,260 and it's only when we look at it in 11 00:00:24,260 --> 00:00:26,390 slow-motion can we really see how the 12 00:00:26,390 --> 00:00:28,490 tongue is unfurling from the mouth and 13 00:00:28,490 --> 00:00:30,210 impacting the insect. 14 00:00:30,210 --> 00:00:33,390 That's Alexis Noel at Georgia Tech. 15 00:00:33,390 --> 00:00:35,830 Noel and her colleagues studied frog tongues 16 00:00:35,830 --> 00:00:37,810 and the fluid mechanics of their spit 17 00:00:37,820 --> 00:00:40,400 to understand how frogs slurp up their prey. 18 00:00:40,400 --> 00:00:44,180 First, Noel studied the physical properties of the tongue. 19 00:00:44,180 --> 00:00:46,720 It was so soft, Noel had to design 20 00:00:46,720 --> 00:00:48,120 special equipment to get an accurate 21 00:00:48,120 --> 00:00:49,280 softness measurement. 22 00:00:49,280 --> 00:00:51,860 "It's even softer than brain tissue. 23 00:00:51,860 --> 00:00:53,580 Even softer than a marshmallow." 24 00:00:53,580 --> 00:00:56,300 That soft tongue comes in handy. 25 00:00:56,300 --> 00:00:59,060 Prey sinks deep into the tongue's surface, 26 00:00:59,060 --> 00:01:02,580 increasing contact for a good grip. 27 00:01:02,580 --> 00:01:04,640 The softness also absorbs force 28 00:01:04,650 --> 00:01:06,960 like a bungee cord so the frog can reel in 29 00:01:06,960 --> 00:01:09,200 a cricket rather than giving it a yank 30 00:01:09,200 --> 00:01:12,020 that might cause separation. 31 00:01:12,020 --> 00:01:13,580 But it's the saliva that temporarily 32 00:01:13,590 --> 00:01:17,400 glues the bug to a frog's tongue. 33 00:01:17,400 --> 00:01:20,520 Frog tongues are like spit-saturated sponges 34 00:01:20,520 --> 00:01:21,900 since their salivary glands 35 00:01:21,900 --> 00:01:24,360 are inside the tongue. 36 00:01:24,360 --> 00:01:26,020 Noel and her colleagues analyzed the 37 00:01:26,030 --> 00:01:28,850 fluid properties of this saliva. 38 00:01:29,660 --> 00:01:33,259 "So I scraped about 17 or 18 frog tongues." 39 00:01:33,259 --> 00:01:35,780 Those spit samples revealed frog saliva is 40 00:01:35,780 --> 00:01:37,780 a shear thinning fluid. 41 00:01:37,780 --> 00:01:40,240 The saliva starts out viscous and sticky, 42 00:01:40,240 --> 00:01:43,420 but when force is applied, it liquefies. 43 00:01:43,420 --> 00:01:45,640 The force of hitting the insect 44 00:01:45,640 --> 00:01:48,260 makes the spit splash up around the bug 45 00:01:48,260 --> 00:01:51,020 "And it is able to penetrate all the tiny cracks 46 00:01:51,020 --> 00:01:52,860 and crevices within the insect 47 00:01:52,860 --> 00:01:55,400 increasing its contact area." 48 00:01:55,400 --> 00:01:57,820 After that impact, the spit thickens again, 49 00:01:57,820 --> 00:02:01,840 trapping the insect in the goo. 50 00:02:01,840 --> 00:02:03,540 It's so sticky that the frog needs to 51 00:02:03,540 --> 00:02:06,060 shove its eyeballs onto its tongue 52 00:02:06,080 --> 00:02:09,160 in order to loosen the spit enough to swallow its morsel. 53 00:02:09,160 --> 00:02:12,140 It's that combination of the soft tongue 54 00:02:12,140 --> 00:02:13,880 and the sticky saliva 55 00:02:13,880 --> 00:02:17,060 that lets frogs scoop up prey in an instant. 56 00:02:17,060 --> 00:02:19,740 Of course not even super spit can help the frog 57 00:02:19,740 --> 00:02:23,020 if it bites off more than it can chew. 58 00:02:23,020 --> 00:02:25,160 For Scientific American, I'm Lydia Chain.