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What the sources say

Bighorn SheepOvis canadensis

Every figure, record and mechanism on the Bighorn Sheep profile was written from a source, and this is the working table behind it: 44 claims checked word for word against these sources. The left column is what the page says. The right column is the source's own words, copied, not paraphrased; a ... marks a cut and[brackets] an insertion. Open any source and check it yourself.

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Source
01

National Wildlife Federation, Wildlife Guide

Bighorn Sheep. National Wildlife Federation, Wildlife Guide.

The page saysHorns weighing up to thirty pounds
The source saysLarge, curved horns—borne by the males, or rams—can weigh up to 30 pounds (14 kilograms), as much as the rest of the bones in the male's body.
The page sayshooves shaped to snag any slight protrusion
The source saysThe outer hooves are modified toenails shaped to snag any slight protrusion, while a soft inner pad provides a grip that conforms to each variable surface.
The page saysGrasses, clover and sedges in warmer months, switching to woody plants like willow and sage in colder months; desert sheep often eat holly and cactus
The source saysIn warmer months, bighorn sheep browses on grasses, clover, and sedges. It transitions to eating woody plants like willow and sage in colder months. In desert areas, bighorn sheep often eat plants such as holly and cacti.
The page saysThe bighorn sheep (Ovis canadensis) has a compact, muscular body, and it is one of two wild sheep species in North America with large horns
The source saysThe bighorn sheep's compact body is muscular ... The bighorn sheep is one of two species of wild sheep in North America with large horns
The page saysMost weigh 73 to 113 kilograms (160 to 250 pounds), but males may weigh more than 159 kilograms (350 pounds) and stand around 102 centimeters (40 inches) at the shoulder
The source saysMost weigh 160 to 250 pounds (73 to 113 kilograms), but males may weigh more than 350 pounds (159 kilograms) and stand around 40 inches (102 centimeters) at the shoulder.
The page saysA ram's curved horns can weigh up to 14 kilograms (30 pounds), as much as the rest of the bones in his body
The source saysLarge, curved horns—borne by the males, or rams—can weigh up to 30 pounds (14 kilograms), as much as the rest of the bones in the male's body.
The page saysHorns that can weigh as much as the rest of his skeleton
The source saysLarge, curved horns—borne by the males, or rams—can weigh up to 30 pounds (14 kilograms), as much as the rest of the bones in the male's body.
The page saysAn older ram's horns can grow over 0.9 meters (three feet) long
The source saysOlder rams have massive horns that can grow over three feet (0.9 meters) long
The page saysIn warmer months they eat grasses, clover and sedges, switching to woody plants like willow and sage in colder months, and desert sheep often eat holly and cactus
The source saysIn warmer months, bighorn sheep browses on grasses, clover, and sedges. It transitions to eating woody plants like willow and sage in colder months. In desert areas, bighorn sheep often eat plants such as holly and cacti.
The page saysA complex four-part stomach lets them eat large portions fast, then retreat to cliffs or ledges to rechew their food, safe from predators
The source saysAs ruminants, grass-eating bighorn sheep have a complex four-part stomach that enables them to eat large portions rapidly before retreating to cliffs or ledges where they can thoroughly rechew and digest their food, safe from predators.
The page saysThough not as agile as mountain goats, bighorns are well equipped for climbing the steep terrain that keeps their predators at bay
The source saysAlthough not as agile as mountain goats, bighorn sheep are well-equipped for climbing the steep terrain that keeps their predators at bay.
The page saysThe outer hoof is a modified toenail shaped to snag any slight protrusion, while a soft inner pad grips and conforms to each surface
The source saysThe outer hooves are modified toenails shaped to snag any slight protrusion, while a soft inner pad provides a grip that conforms to each variable surface.
The page saysTheir mountain habitat has ledges sometimes only five centimeters (two inches) wide, and it gives cover from predators such as coyotes, golden eagles, mountain lions, bears and Canada lynx
The source saysTheir steep mountainous habitat, with ledges sometimes only two inches (five centimeters) wide, provides cover from predators such as coyotes, golden eagles, mountain lions, bears, and Canada lynx
The page saysEwes grow horns too, but theirs stay short with only a slight curve
The source saysFemales, or ewes, also have horns, but they are short with only a slight curvature.
The page saysTheir steep habitat has ledges sometimes only five centimeters (two inches) wide
The source saysTheir steep mountainous habitat, with ledges sometimes only two inches (five centimeters) wide
The page saysThe species has three living subspecies: the Rocky Mountain, Sierra Nevada and desert bighorns.
The source says"bighorn sheep" is one species, with three living subspecies: the Rocky Mountain bighorn sheep (Ovis canadensis canadensis), the Sierra Nevada bighorn sheep (Ovis canadensis sierrae)—formerly called the California bighorn sheep, and the desert bighorn sheep (Ovis canadensis nelsoni).

Source
02

Rocky Mountain National Park, National Park Service

Bighorn Sheep. Rocky Mountain National Park, National Park Service.

The page sayshead-first charges at up to forty mph
The source saysrams face each other, rear up on hind legs and pitch forward at speeds up to 40 mph
The page saysthe thick, bony skull absorbs repeated head-on clashes at up to 40 mph with little injury to the ram
The source saysrams face each other, rear up on hind legs and pitch forward at speeds up to 40 mph ... Bighorn sheep skulls are thick and bony to absorb this repeated impact with little physical injury to the ram.
The page saysA bighorn's lifespan is about 10 years
The source saysThe lifespan of bighorn sheep is approximately 10 years.
The page saysMating season comes in the fall, when rams fight for dominance or mating rights
The source saysMating occurs in the fall when rams use their horns as weapons of battle to fight for dominance or female mating rights.
The page saysThey rear up on their hind legs and pitch forward at each other at up to 64 kilometers per hour (40 mph), and the crash of horns can be heard up to a mile away
The source saysrams face each other, rear up on hind legs and pitch forward at speeds up to 40 mph. The loud crash of horns signals contact and can be heard up to one mile away.Note: 40 mph converted to 64 km/h (40 mph = 64.4 km/h); the quote itself only states 40 mph.
The page saysThe ritual repeats until one ram concedes and walks away
The source saysThis ritual is repeated until one animal concedes and walks away.
The page saysThe skull is built for it: thick and bony, it absorbs the repeated impact with little injury to the ram
The source saysBighorn sheep skulls are thick and bony to absorb this repeated impact with little physical injury to the ram.
The page saysRival rams rear up on their hind legs and pitch forward at speeds up to 64 kilometers per hour (40 miles per hour). The loud crash of horns can be heard up to a mile away.
The source saysrams face each other, rear up on hind legs and pitch forward at speeds up to 40 mph. The loud crash of horns signals contact and can be heard up to one mile away.Note: 40 mph converted to 64 km/h (40 mph = 64.4 km/h); the quote itself only states 40 mph.
The page saysrear up and pitch forward at each other at up to 64 kilometers per hour
The source saysrams face each other, rear up on hind legs and pitch forward at speeds up to 40 mph. The loud crash of horns signals contact and can be heard up to one mile away.Note: vibe.reason (#692 re-home); 40 mph converted to 64 km/h
The page saysThe ritual repeats until one ram concedes and walks away
The source saysThis ritual is repeated until one animal concedes and walks away.Note: vibe.reason (#692 re-home)

Source
03

Animal Diversity Web, University of Michigan

Ovis canadensis (bighorn sheep). Animal Diversity Web, University of Michigan.

The page saysAlpine meadows, grassy mountain slopes and foothills near rugged, rocky cliffs in the Rocky Mountains
The source saysOvis canadensis canadensis inhabits alpine meadows, grassy mountain slopes and foothill country in proximity to rugged, rocky cliffs and bluffs.Note: ADW's habitat line is for the Rocky Mountain subspecies O. c. canadensis; the range quote places the species in the Rocky Mountains.
The page saysplus a desert subspecies from Nevada and California to west Texas and Mexico
The source saysOvis canadensis is found in the Rocky Mountains from southern Canada to Colorado, and as a desert subspecies (O. c. nelsoni) from Nevada and California to west Texas and south into Mexico.
The page saysA double-layered skull shored with struts of bone and a massive tendon linking skull to spine
The source saysBighorn sheep have double-layered skulls shored with struts of bone for battle protection. They also have a broad, massive tendon linking skull and spine to help the head pivot and recoil from blows.
The page saysIt is double-layered and shored with struts of bone, while a broad, massive tendon linking skull to spine helps the head pivot and recoil from blows
The source saysBighorn sheep have double-layered skulls shored with struts of bone for battle protection. They also have a broad, massive tendon linking skull and spine to help the head pivot and recoil from blows.
The page saysBighorns live in the Rocky Mountains from southern Canada to Colorado, and a desert subspecies ranges from Nevada and California to west Texas and south into Mexico
The source saysOvis canadensis is found in the Rocky Mountains from southern Canada to Colorado, and as a desert subspecies (O. c. nelsoni) from Nevada and California to west Texas and south into Mexico.
The page saysdangerLevel: Low
The source saysThere are no known negative effects of bighorn sheep on humans.

Source
04

AnAge: The Animal Ageing and Longevity Database, Human Ageing Genomic Resources

Ovis canadensis. AnAge: The Animal Ageing and Longevity Database, Human Ageing Genomic Resources.

The page saysthe record in captivity is 20.6 years
The source saysRecord longevity in captivity is 20.6 years

Source
05

Festa-Bianchet 2020

Festa-Bianchet (2020). Ovis canadensis. The IUCN Red List of Threatened Species 2020: e.T15735A22146699.

The page saysLeast Concern
The source saysIUCN Red List category: Least Concern (LC).Note: read through GBIF's copy of the Red List per docs/fact-check.md; the assessment text itself (doi: 10.2305/iucn.uk.2020-2.rlts.t15735a22146699.en) is a hand check beyond the category.

Source
06

Coltman et al. 2003

Coltman et al. (2003). Undesirable evolutionary consequences of trophy hunting. Nature.

The page saysIn one wild population, sport hunting drove evolution: rams' body weight and horn size declined significantly over time
The source saysHere we show that in an evolutionary response to sport hunting of bighorn trophy rams (Ovis canadensis) body weight and horn size have declined significantly over time. ... based on a partly genetically reconstructed pedigree from a 30-year study of a wild population in which trophy hunting targeted rams with rapidly growing horns
The page saysA 30-year study of that population, where trophy hunting targeted rams with rapidly growing horns, found both traits were highly heritable
The source saysbased on a partly genetically reconstructed pedigree from a 30-year study of a wild population in which trophy hunting targeted rams with rapidly growing horns ... Both traits were highly heritable
The page saysThe rams hunters shot had higher genetic value for weight and horn size than the rams they spared, and they were shot at an early age, so they did not achieve high breeding success
The source saystrophy-harvested rams were of significantly higher genetic 'breeding value' for weight and horn size than rams that were not harvested. Rams of high breeding value were also shot at an early age, and thus did not achieve high reproductive success.
The page saysUnder unrestricted trophy hunting, the population's genetic averages for both traits fell, leaving smaller-horned, lighter rams and fewer trophies
The source saysDeclines in mean breeding values for weight and horn size therefore occurred in response to unrestricted trophy hunting, resulting in the production of smaller-horned, lighter rams, and fewer trophies.
The page saysYes, in at least one long-studied wild population
The source saysbased on a partly genetically reconstructed pedigree from a 30-year study of a wild population in which trophy hunting targeted rams with rapidly growing horns
The page saysA 30-year study found that horn size and body weight were both highly heritable there
The source saysbased on a partly genetically reconstructed pedigree from a 30-year study of a wild population in which trophy hunting targeted rams with rapidly growing horns ... Both traits were highly heritable
The page saysrams of high genetic value for both traits were shot at an early age, so they did not achieve high breeding success
The source saystrophy-harvested rams were of significantly higher genetic 'breeding value' for weight and horn size than rams that were not harvested. Rams of high breeding value were also shot at an early age, and thus did not achieve high reproductive success.
The page saysUnder unrestricted trophy hunting, the population's genetic averages for weight and horn size declined, leaving smaller-horned, lighter rams
The source saysDeclines in mean breeding values for weight and horn size therefore occurred in response to unrestricted trophy hunting, resulting in the production of smaller-horned, lighter rams, and fewer trophies.

Source
07

Jones et al. 2022

Jones et al. (2022). Desert bighorn sheep habitat selection, group size, and mountain lion predation risk. The Journal of Wildlife Management.

The page saysA 2013 to 2017 GPS-collar study of two Arizona desert populations found that sheep using more rugged areas and steeper slopes were less likely to be killed by a mountain lion
The source saysWe fit 103 bighorn sheep (81 females and 22 males) with global positioning system radio‐collars in 2 Arizona populations from 2013 to 2017 ... The use of more rugged areas and steeper slopes decreased the risk of mortality due to mountain lion predation, consistent with presumed predator avoidance strategies.Note: 'desert' is from the paper's title, 'Desert bighorn sheep habitat selection, group size, and mountain lion predation risk'.
The page saysBigger groups also cut the risk, though the benefit became marginal at about ten sheep a group
The source saysIncreased group size decreased risk of bighorn sheep mortality due to mountain lion predation but this effect became marginal at approximately 10 individuals/group.

How the table was made: a writer drafted the profile from these sources and logged each claim with its quote, a reviewer with nothing but this table checked every sentence said no more than its quote, and a script confirmed each quote appears word for word in the source. The method is in the site'sAbout page.