While boating down the Yukon River during the hottest summer recorded in Alaska (1915, when Fort Yukon reached 100 degrees Fahrenheit), missionary Hudson Stuck wrote about the wildlife that most bothered his party.<\/p>\n
\u201cWith the failure of a little breeze and the overcasting of the sky, the weather grows oppressively sultry and a swarm of horse-flies, or moose-flies as they are called in these parts, makes appearance \u2014 large venomous insects that bite a piece out of one\u2019s flesh when they alight.\u201d<\/p>\n
A century later, the helmeted flies almost the size of a moose nugget maintain a healthy presence along Alaska\u2019s waterways. The flies from the family Tabanidae (called horse and deer flies in other places) drive moose to gallops of terror. The big flies seek mammals, including you, for meals of blood that allow them to produce more flies.<\/p>\n
The creatures are stout enough to absorb the smack of a palm and then fly away. With evolved stealth, they feather-land on skin. Soon after, the victim feels the pierce of a needle many times worse than a mosquito bite. Horse and deer fly expert James Goodwin of Jarvis Christian College in Texas explains: \u201cThe female\u2019s mouthparts include two pairs of cutting blades,\u201d he wrote in an email. \u201cA female literally chews or cuts through the skin with these blades, creating a wound that serves as a pool which fills up with blood.\u201d<\/p>\n
If left unmolested \u2014 which almost never happens when a fly slices a human \u2014 the fly laps blood until its abdomen is about to burst. Biologist J.L. Webb, on assignment to study horse flies in California and Nevada in the 1920s, pulled out his stopwatch when he witnessed a fly on a \u201cperfectly calm\u201d cow. \u201cThe fly fed to apparent satiety in 11 minutes and 10 seconds,\u201d Webb reported.<\/p>\n
As is the case with mosquitoes and other biting flies that have prevented humans from overpopulating Alaska, the females are the ones to fear. The adult males have no flesh-cutting apparatus, surviving on a diet of nectar and pollen. From an evolutionary perspective it\u2019s hard to fault the females in their quest for protein-rich meals. We are warm, slow-moving and contain the nectar of life.<\/p>\n
Sensors on the flies\u2019 large heads detect the carbon dioxide we emit and the heat of our bodies, along with our clothing and silhouettes and other features that make us stand out from the alder bushes. Their multicolored compound eyes sometimes feature bold stripes, which may be how males and females of the same species recognize one another.<\/p>\n
Thirty to 40 different species of the giant flies buzz the air of Alaska, some of them the same type that harass cattle and horses in Texas. The winged adults only live three or four weeks here, just as they do down south. Entomologists have found the big flies everywhere on the planet except Hawaii, Greenland and Iceland.<\/p>\n
And, while everyone in more southern places calls them horse flies, Hudson Stuck wrote that moose fly is a much better fit for the Alaska version.<\/p>\n
\u201cHere we are annoyed by them almost beyond endurance,\u201d he wrote on his sweltering river trip of a century ago. \u201cAnd not a horse within 100 miles.\u201d<\/p>\n
\u2022 Since the late 1970s, the University of Alaska Fairbanks\u2019 Geophysical Institute has provided this column free in cooperation with the UAF research community. Ned Rozell is a science writer for the Geophysical Institute. A version of this column appeared in 2012.<\/p>\n","protected":false},"excerpt":{"rendered":"
While boating down the Yukon River during the hottest summer recorded in Alaska (1915, when Fort Yukon reached 100 degrees Fahrenheit), missionary Hudson Stuck wrote about the wildlife that most bothered his party. \u201cWith the failure of a little breeze and the overcasting of the sky, the weather grows oppressively sultry and a swarm of […]<\/p>\n","protected":false},"author":107,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_stopmodifiedupdate":false,"_modified_date":"","wds_primary_category":7,"footnotes":""},"categories":[7],"tags":[149],"yst_prominent_words":[],"class_list":["post-22787","post","type-post","status-publish","format-standard","hentry","category-life","tag-outdoors"],"_links":{"self":[{"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/posts\/22787","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/users\/107"}],"replies":[{"embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/comments?post=22787"}],"version-history":[{"count":0,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/posts\/22787\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/media?parent=22787"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/categories?post=22787"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/tags?post=22787"},{"taxonomy":"yst_prominent_words","embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/yst_prominent_words?post=22787"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}