\u201cBy working together, killer whales can conserve energy and use the dolphins as radar-equipped scouts to increase their chances of finding large Chinook salmon at deeper depths. <\/p>\n
\u201cIn return, the dolphins gain predator protection and access to scraps from one of the ocean\u2019s most prized fish,\u201d said Andrew Trites, director of the Marine Mammal Research Unit at the University of British Columbia\u2019s Institute for the Oceans and Fisheries. \u201cIt\u2019s a win-win for everyone involved.\u201d<\/p>\n
Trites and his co-authors of a study published on Friday in the journal Scientific Reports also noted \u201crare occasions\u201d in which dolphins were seen briefly holding and releasing large salmon near the surface, potentially to aid nearby orcas who could tear the fish into more manageable pieces. <\/p>\n
Pacific white-sided dolphins do not have a way to break up their prey before ingestion and so swallow it whole.<\/p>\n
\u201cThe lack of competitive or antagonistic behaviour suggests mutual tolerance that yields reciprocal benefit for both species,\u201d the researchers concluded.<\/p>\n
Pacific white-sided dolphins and northern resident orcas have been known to interact before, but the purpose of those interactions was never clear. <\/p>\n
The footage captured by the researchers is \u201cthe first video of its kind\u201d to show the animals hunting together, the researchers said in a statement marking the study\u2019s release. Understanding the exact nature of the two species\u2019 behaviour would require further study.<\/p>\n
Still, the scientists wrote, the data points to \u201cmore than incidental co-occurrences\u201d. <\/p>\n
The orcas dove deeper and travelled farther while hunting when dolphins were around.<\/p>\n
Study co-author Keith Holmes, a drone pilot with the Hakai Institute, an ecological research centre in Canada, seemed certain that some kind of co-ordination was occurring from the moment he spotted the orcas and dolphins at work. <\/p>\n
He first noticed the behaviour while doing fieldwork on a different project for the University of British Columbia.<\/p>\n
\u201cFrom above, you could see this incredible amount of activity,\u201d Holmes said. \u201cIt was clear that there was some sort of communication happening and they were actively foraging together.\u201d<\/p>\n
Dalhousie University oceanographer Sarah Fortune, the study\u2019s lead author, with Holmes, Trites and Xi Cheng, used drones and data from tracking devices to study the whales\u2019 behaviour.<\/p>\n
The trackers, which were temporarily attached to healthy whales via suction cup, sent location data, underwater video footage and audio, including the whales\u2019 vocalisations and sounds associated with feeding. (Think the audible crunch of a Chinook salmon caught in an orca\u2019s jaw.)<\/p>\n
The underwater footage enabled the researchers to closely monitor orca feeding behaviour, from the hunt to the kill to the eventual sharing of the meal with other members of the pod – and even an opportunistic dolphin here and there.<\/p>\n
The field work was conducted over the course of 15 days in August 2020.<\/p>\n
Apparent co-operation between the dolphins and orcas \u201cexclusively occurred during foraging events and involved co-ordinated movements – such as killer whales trailing dolphins – and synchronised acoustic activity,\u201d the researchers wrote.<\/p>\n
The orcas also didn\u2019t appear to mind the dolphins picking at their leftovers. \u201cNeither the aerial drone nor underwater video data revealed any signs of aggression, such as tail slaps, biting or raking appendages,\u201d the scientists wrote, behaviours that might have pointed to the orcas trying to ward off unwelcome guests.<\/p>\n
\u201cKiller whales were also never observed fleeing or avoiding the dolphins,\u201d they added. \u201cInstead, the killer whales disproportionately oriented toward the dolphins and mirrored their swimming and diving movements.\u201d<\/p>\n
Researchers have previously observed Pacific white-sided dolphins, northern resident killer whales and also Dall\u2019s porpoises travelling together and even playing off the coast of British Columbia. <\/p>\n
Those scientists, working separately from the authors of the study, theorised that the porpoises and dolphins chose to stick by the friendlier orcas to fend off the attention of more dangerous, predatory orcas, who have been known to hunt and play vicious games with other sea creatures, and sometimes kill them in the process.<\/p>\n
Sign up to Herald Premium Editor\u2019s Picks<\/a>, delivered straight to your inbox every Friday. Editor-in-Chief Murray Kirkness picks the week\u2019s best features, interviews and investigations. Sign up for Herald Premium here<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"\u201cBy working together, killer whales can conserve energy and use the dolphins as radar-equipped scouts to increase their…\n","protected":false},"author":2,"featured_media":183011,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[8831,41220,67917,33224,43893,1866,8321,12632,64573,9641,78,3242,111,139,69,76836,13572,53295,116033,18994,116035,9621,53917,147,544,4755,73819,1361,61,122,3608,6923,116034,14036,406,6730],"class_list":["post-183010","post","type-post","status-publish","format-standard","has-post-thumbnail","category-wildlife","tag-an","tag-capture","tag-dolphin","tag-dolphins","tag-fact","tag-find","tag-fish","tag-friend","tag-hungry","tag-idea","tag-in","tag-large","tag-new-zealand","tag-newzealand","tag-nz","tag-orcas","tag-pacific","tag-prey","tag-prized","tag-resigned","tag-salivating","tag-salmon","tag-sampling","tag-science","tag-some","tag-swallow","tag-teaming","tag-that","tag-to","tag-unlikely","tag-were","tag-what","tag-whitesided","tag-whole","tag-wildlife","tag-would"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/183010","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=183010"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/183010\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/183011"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=183010"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=183010"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=183010"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}