Some southern right whales take a longer route toward Antarctica but still reach their feeding grounds on time.<\/p>\n
Southern right whales leaving New Zealand\u2019s Auckland Islands face a long swim to their feeding grounds south of Australia. Some make that journey even longer by heading toward Antarctica first.<\/p>\n
The surprising part is that this detour does not seem to make them late. <\/p>\n
Whales taking the longer route leave earlier and reach the feeding grounds around the same time as those that travel more directly.<\/p>\n
These journeys offer a glimpse of how whales find their way across a vast ocean. <\/p>\n
They also suggest that the animals can change routes, a flexibility that may become valuable as ocean conditions change.<\/p>\n
Two routes to food<\/p>\n
Southern right whales, known in M\u0101ori as tohor\u0101<\/a>, gather around the Auckland Islands to socialize, mate, and give birth. <\/p>\n They spend roughly May through September there, then travel toward waters south of Australia to feed.<\/p>\n Researchers led by Leena Riekkola and Xuelei Zhang studied these journeys with colleagues at the University of Auckland<\/a>. <\/p>\n Between 2020 and 2022, the team attached satellite tags<\/a> to 25 whales.<\/p>\n Twenty-one tags provided enough information to map the outward migration. <\/p>\n Ten whales headed west or northwest, taking a fairly direct route toward their feeding grounds.<\/p>\n The other 11 first swam south or southwest toward Antarctica before turning northwest. On a map, their journeys looked roughly like the letter L.<\/p>\n Leaving early buys time<\/p>\n The whales taking the detour left in late July on average. Those following the direct route waited until late August, giving the first group about a month\u2019s head start.<\/p>\n Only 16 tags continued sending information until the whales reached their feeding grounds. <\/p>\n Among those animals, the longer trips averaged 64 days, while the direct journeys took 42 days.<\/p>\n Despite spending about three extra weeks traveling, the detouring whales arrived at roughly the same time as the others. <\/p>\n Both groups reached the area in early October on average, with no clear statistical difference in their arrival dates.<\/p>\n Their timing matched the seasonal peak in phytoplankton<\/a>, the tiny algae that support much of the ocean\u2019s food web. <\/p>\n The researchers suspect the whales may be timing their arrival to this productive season, although the tracking records cannot prove that.<\/p>\n Why take the detour?<\/p>\n An early start explains how a whale can spend longer traveling and still arrive on time. What remains puzzling is why it would swim farther in the first place.<\/p>\n The researchers think the routes may reflect different ways of balancing time and energy. <\/p>\n Riekkola compared those possible choices to a road trip, where some travelers may conserve energy while others try to make up for a late start.<\/p>\n Whales on the direct route swam slightly faster, but the difference was small. <\/p>\n The team\u2019s statistical tests gave mixed results, so it is unclear whether that extra speed mattered much to the animals.<\/p>\n Body size, sex, and body condition did not clearly explain the routes either. <\/p>\n Those comparisons were limited because some measurements were missing and all the tagged whales were mature animals in good condition.<\/p>\n Whales can change routes<\/p>\n The tracking records also showed that a whale\u2019s route is not necessarily fixed. <\/p>\n Five animals provided information from two outward migrations in consecutive years.<\/p>\n Three took the longer route both times. The other two followed the direct route one year and the detour the next.<\/p>\n One whale that switched was a female traveling with a calf<\/a> during the first year. <\/p>\n Researchers presumed she had no calf the following year, raising the possibility that having a youngster alongside her influenced the journey.<\/p>\n Only two tagged whales were mothers with calves, and both left later and traveled directly. <\/p>\n That is too few to establish a pattern, but following more mothers could help explain how caring for a calf affects migration.<\/p>\n Finding an ocean path<\/p>\n The longer journeys had another feature in common: many whales turned north in similar ocean conditions. <\/p>\n Most made the turn near the southern edge of the Antarctic Circumpolar Current<\/a>, which flows around Antarctica, and above shallower seafloor.<\/p>\n Their turning points also matched a particular range in the angle<\/a> of Earth\u2019s magnetic field. Sea\u00a0ice<\/a>\u00a0offered a weaker clue, because most whales turned well away from its edge.<\/p>\n Any of these features might help researchers understand how whales navigate<\/a>. <\/p>\n For now, though, a match on a map does not show that the animals actually use it to find their way.<\/p>\n Learning from other whales<\/p>\n Southern right whales tend to return to feeding grounds their mothers took them to. <\/p>\n That makes their ability to switch routes especially interesting, because a whale may eventually travel a different way from the one it learned as a calf.<\/p>\n Other whales could play a part in that learning<\/a>. In 2020, two tagged animals followed closely matching paths for about 250 miles (400 km), possibly remaining near enough to hear each other.<\/p>\n Researchers need to follow more whales over several years to understand how they learn and change routes. <\/p>\n Study co-author Emma Carroll, an associate professor at the University of Auckland, sees potential value in that ability to adjust.<\/p>\n \u201cA population that can adapt its behavior has a better chance of coping with changing seas,\u201d said Carroll.<\/p>\n The study is published in the journal\u00a0Proceedings of the Royal Society B<\/a>.<\/p>\n \u2014\u2013<\/p>\n Like what you read? Subscribe to our newsletter<\/a> for engaging articles, exclusive content, and the latest updates.<\/p>\n Check us out on EarthSnap<\/a>, a free app brought to you by Eric Ralls<\/a> and Earth.com.<\/p>\n \u2014\u2013<\/p>\n","protected":false},"excerpt":{"rendered":"Some southern right whales take a longer route toward Antarctica but still reach their feeding grounds on time.…\n","protected":false},"author":2,"featured_media":633021,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[111,139,69,147,406],"class_list":["post-633020","post","type-post","status-publish","format-standard","has-post-thumbnail","category-wildlife","tag-new-zealand","tag-newzealand","tag-nz","tag-science","tag-wildlife"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/633020","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=633020"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/633020\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/633021"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=633020"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=633020"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=633020"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}