{"id":571843,"date":"2010-05-20T12:00:02","date_gmt":"2010-05-20T16:00:02","guid":{"rendered":"http:\/\/blogs.discovermagazine.com\/notrocketscience\/?p=1656"},"modified":"2010-05-20T12:00:02","modified_gmt":"2010-05-20T16:00:02","slug":"tree-frogs-shake-their-bums-to-send-threatening-vibes-not-exactly-rocket-science","status":"publish","type":"post","link":"https:\/\/mereja.media\/index\/571843","title":{"rendered":"Tree frogs shake their bums to send threatening vibes | Not Exactly Rocket Science"},"content":{"rendered":"<p style=\"text-align:center;\"><a rel=\"nofollow\"  href=\"http:\/\/blogs.discovermagazine.com\/notrocketscience\/files\/2010\/05\/Redeyed_treefrog.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-1657\" title=\"Camouflage FAIL\" src=\"http:\/\/blogs.discovermagazine.com\/notrocketscience\/files\/2010\/05\/Redeyed_treefrog.jpg\" alt=\"Redeyed_treefrog\" width=\"600\" height=\"287\"\/><\/a><\/p>\n<p>Two males <a rel=\"nofollow\"  href=\"http:\/\/www.rainforest-alliance.org\/resources.cfm?id=tree_frog\">red-eyed tree frogs<\/a> square off over a female. Fisticuffs will soon ensue and as a final challenge to each other, the males&#8230; er&#8230; vigorously shake their bums at each other. Their quivering buttocks shake the plants they sit on, sending threatening vibrations towards their rival. This secret line of communication has just been uncovered by <a rel=\"nofollow\"  href=\"http:\/\/people.bu.edu\/mpod3\/\">Michael Caldwell<\/a> from Boston University. To decipher these messages, he has used a hi-tech combination of infrared cameras, saplings rigged with accelerometers and even a cybernetic Robofrog.<\/p>\n<p><iframe loading=\"lazy\" class=\"embeddedvideo\" type=\"application\/x-shockwave-flash\" width=\"600\" height=\"480\" src=\"http:\/\/www.youtube.com\/v\/Q8s0kl0ZIrk&amp;hl=en_GB&amp;fs=1&amp;color1=0x2b405b&amp;color2=0x6b8ab6\"><\/iframe><\/p>\n<p><span id=\"more-1656\"><\/span>During mating season, male red-eyed tree frogs gather in the rainforests of Panama to compete for females with dramatic multimedia performances, involving calls and visual signals. Studying these messages can be difficult because the frogs communicate at night. A white lamp would kill their natural behaviour, prompting males to become far more restrained than usual, save in the presence of females. Instead, Caldwell watched them under an infrared light. He pitted 38 pairs of frogs against each other, on plants fitted with accelerometers.<\/p>\n<p><a rel=\"nofollow\"  href=\"http:\/\/blogs.discovermagazine.com\/notrocketscience\/files\/2010\/05\/Frog-vs-frog.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignright size-full wp-image-1659\" title=\"The time for bum-shaking has passed. Now is the time for skin on skin. \" src=\"http:\/\/blogs.discovermagazine.com\/notrocketscience\/files\/2010\/05\/Frog-vs-frog.jpg\" alt=\"Frog-vs-frog\" width=\"200\" height=\"230\"\/><\/a>The frogs made two types of calls (chuckles and chacks), raised their bodies off their leaves and kicked out with their legs. And in every aggressive encounter, they also rapidly shook their bums, producing vibrations with a consistent high-pitched tone. The contests would last for anywhere from a minute to an hour. If the signalling didn\u2019t work, the time was talk was over and violence ensued. Males would wrestle with each other, sometimes for hours on end (see right).<\/p>\n<p>The vibrations, or \u2018tremulations\u2019, were clearly very important and were usually the last line of negotiation before battle commenced. The victor almost always shook for more time, created longer-lasting vibrations and was more likely to have the last shake. The frequencies of the vibrations were fairly constant although victors tended to produce higher-pitched tremulations if they were smaller than their rivals or similarly sized.<\/p>\n<p><iframe loading=\"lazy\" class=\"embeddedvideo\" type=\"application\/x-shockwave-flash\" width=\"600\" height=\"480\" src=\"http:\/\/www.youtube.com\/v\/tYiIhrR3kqg&amp;hl=en_GB&amp;fs=1&amp;color1=0x2b405b&amp;color2=0x6b8ab6\"><\/iframe><\/p>\n<p>Of course, the <em>sight<\/em> of a frog shaking its bum is also quite striking, but Caldwell found that a male was no more likely to tremulate when his opponent was facing him than when he was turned away. This strongly suggests that the vibrations themselves were carrying information. In fact, every part of the male\u2019s repertoire sends distinctive tremors through the plant, including his chuckles. Even the kicking legs seem to brush past the plant stems in the style of a musician plucking a guitar string.<\/p>\n<p>Caldwell\u2019s observations had been informative but he wanted to <em>test <\/em>the frogs\u2019 behaviour. Enter Robofrog \u2013 a model equipped with an electric shaker and a prime directive is to provoke other males. When he made his own vibrations, living males responded accordingly and aggressively. By contrast, nothing happened when he sat still, when he made visual signs without tremulating, or when Caldwell exposed the test frogs to white noise vibrations in Robofrog\u2019s absence.<\/p>\n<p style=\"text-align:center;\"><a rel=\"nofollow\"  href=\"http:\/\/blogs.discovermagazine.com\/notrocketscience\/files\/2010\/05\/Robofrog.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-1660\" title=\"\"Come quietly or there will be... trouble.\"\" src=\"http:\/\/blogs.discovermagazine.com\/notrocketscience\/files\/2010\/05\/Robofrog.jpg\" alt=\"Robofrog\" width=\"600\" height=\"297\"\/><\/a><\/p>\n<p><iframe loading=\"lazy\" class=\"embeddedvideo\" src=\"http:\/\/www.youtube.com\/v\/yZ_GMEiLEA0&#038;hl=en_GB&#038;fs=1&#038;color1=0x2b405b&#038;color2=0x6b8ab6\" type=\"application\/x-shockwave-flash\" width=\"600\" height=\"480\"><\/iframe><\/p>\n<p>All in all, these experiments show that competing red tree frogs use a secret channel of communication that most human observers would be completely unaware of. Vibrations are an excellent way of conveying messages in the rainforest, when the combination of darkness and dense foliage might prevent the conversers from seeing each other clearly. Exactly what they say is unclear, but they could provide information about the contender\u2019s motivation or size. And they\u2019re undoubtedly aggressive \u2013 the tree frog\u2019s version of smack-talk.<\/p>\n<p>So far, the red-eyed tree frog is the first back-boned animal that\u2019s been clearly shown to communicate by shaking the surface it sits on. But Caldwell suspects that it\u2019s far from the only one, especially since many other species are highly sensitive to vibrations. Tree-dwellers are probably particularly good at this, especially ones with larger bodies that can shake their supports more strongly.<\/p>\n<p>Candidates include the male <a rel=\"nofollow\"  href=\"http:\/\/en.wikipedia.org\/wiki\/Veiled_Chameleon\">veiled chameleon<\/a>, which shakes the branches it sits on in the presence of a female, and the female South Asian common tree frog, which seems to attract mates by tapping her toes on the plants that encircle their breeding sites. On the ground, and on a<em> much <\/em>bigger scale, elephants could also use vibrations as a sort of <a rel=\"nofollow\"  href=\"http:\/\/www.oaklandzoo.org\/conservation-programs\/conservation-on-site\/elephant-seismic-communication\/\">\u2018seismic signal\u2019<\/a>. Nature is probably full of such hidden conversations, spoken in rumbles and tremors.<\/p>\n<p><strong>Reference<\/strong><strong>: <\/strong>Current Biology <a rel=\"nofollow\"  href=\"http:\/\/dx.doi.org\/10.1016\/j.cub.2010.03.069\">http:\/\/dx.doi.org\/10.1016\/j.cub.2010.03.069<\/a><\/p>\n<p><strong>Photos and videos<\/strong> by Michael Caldwell<\/p>\n<p><strong>More on frogs: <\/strong><\/p>\n<ul>\n<li><a rel=\"nofollow\" title=\"Permanent Link to Seven habits of highly successful toads\">Seven habits of highly successful toads<\/a><\/li>\n<li><a rel=\"nofollow\" title=\"Permanent Link to South African wildlife &#x002013; Foamy nest frog\">South African wildlife \u2013 Foamy nest frog<\/a><\/li>\n<li><a rel=\"nofollow\" title=\"Permanent Link to Common pesticide is good news for parasites, bad news for frogs\">Common pesticide is good news for parasites, bad news for frogs<\/a><\/li>\n<li><a rel=\"nofollow\" title=\"Permanent Link to &#x002018;Wolverine&#x002019; frogs pop retractable claws from their toes\">\u2018Wolverine\u2019 frogs pop retractable claws from their toes<\/a><\/li>\n<li><a rel=\"nofollow\" title=\"Permanent Link to First lungless frog discovered in Borneo\">First lungless frog discovered in Borneo<\/a><\/li>\n<\/ul>\n<p><a rel=\"nofollow\"  href=\"http:\/\/twitter.com\/edyong209\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/blogs.discovermagazine.com\/notrocketscience\/files\/2009\/12\/Twitter.jpg\" alt=\"Twitter.jpg\" width=\"125\" height=\"38\"\/><\/a> <a rel=\"nofollow\"  href=\"http:\/\/www.facebook.com\/pages\/Not-Exactly-Rocket-Science\/209972267204?ref=ts\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/blogs.discovermagazine.com\/notrocketscience\/files\/2009\/12\/Facebook.jpg\" alt=\"Facebook.jpg\" width=\"125\" height=\"38\"\/><\/a> <a rel=\"nofollow\"  href=\"http:\/\/feeds.feedburner.com\/notrocketscience\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/blogs.discovermagazine.com\/notrocketscience\/files\/2009\/12\/Feed.jpg\" alt=\"Feed.jpg\" width=\"125\" height=\"38\"\/><\/a> <a rel=\"nofollow\"  href=\"http:\/\/www.amazon.com\/Not-Exactly-Rocket-Science-Yong\/dp\/1409242285\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/blogs.discovermagazine.com\/notrocketscience\/files\/2009\/12\/Book.jpg\" alt=\"Book.jpg\" width=\"125\" height=\"38\"\/><\/a><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/feeds.feedburner.com\/~r\/DiscoverMag\/~4\/A9wRGoggQIE\" height=\"1\" width=\"1\"\/><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Two males red-eyed tree frogs square off over a female. Fisticuffs will soon ensue and as a final challenge to each other, the males&#8230; er&#8230; vigorously shake their bums at each other. Their quivering buttocks shake the plants they sit on, sending threatening vibrations towards their rival. This secret line of communication has just been [&hellip;]<\/p>\n","protected":false},"author":641,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[],"class_list":["post-571843","post","type-post","status-publish","format-standard","hentry","category-news"],"_links":{"self":[{"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/posts\/571843","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/users\/641"}],"replies":[{"embeddable":true,"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/comments?post=571843"}],"version-history":[{"count":0,"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/posts\/571843\/revisions"}],"wp:attachment":[{"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/media?parent=571843"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/categories?post=571843"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mereja.media\/index\/wp-json\/wp\/v2\/tags?post=571843"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}