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What the sources say

Timber RattlesnakeCrotalus horridus

Every figure, record and mechanism on the Timber Rattlesnake profile was written from a source, and this is the working table behind it: 47 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

Smithsonian's National Zoo

Timber rattlesnake. Smithsonian's National Zoo.

The page saysForested hills, swamps and river floodplains across the eastern United States
The source saysTimber rattlesnakes live in a variety of habitats, including mountainous or hilly forests, hardwood or pine forests, swamps and river floodplainsNote: stats.habitat
The page saysMice, shrews, chipmunks and squirrels, plus birds, lizards and amphibians
The source saysprimarily eat small- to medium-sized rodents, such as mice, shrews, chipmunks and squirrels. They also eat birds, lizards and amphibians.Note: stats.diet
The page saysThe timber rattlesnake is a large, heavy-bodied pit viper that hunts by waiting.
The source saysLike other members of the pit viper family, the timber rattlesnake has a large, heavy-bodied appearance.Note: also large heavy-bodied
The page saysstrikes, bites and injects venom
The source saysquickly striking, biting and injecting venom into passing prey
The page saysIts meals are mainly small to medium rodents like mice, shrews, chipmunks and squirrels, with birds, lizards and amphibians as extras.
The source saysprimarily eat small- to medium-sized rodents, such as mice, shrews, chipmunks and squirrels. They also eat birds, lizards and amphibians.
The page saysAdults typically reach 2.5 to 5 feet (0.76 to 1.5 meters), and there are reports of snakes up to 7 feet (2 meters).
The source saysAdults typically reach lengths of 2.5-5 feet (.76-1.5 meters), but there are reports of timber rattlesnakes growing up to 7 feet (2 meters) long.
The page saysThe rattle is made of loosely attached keratin segments, the same substance as human hair and fingernails.
The source saysLoose sections of the tail made of keratin (the same substance as human hair and fingernails) form the characteristic rattles or "buttons" at the tip of the timber rattlesnake's tail.Note: DEC: loosely attached segments made of keratin
The page saysA young snake has just one button
The source saysYoung rattlesnakes resemble adults, except that they have only one button on their tail
The page saysWhen threatened, the snake props itself up and shakes the rattle, and the segments press together with a rapid, crisp sound.
The source saysWhen threatened, it props itself up and shakes its rattle, which presses the buttons together producing a rapid, crisp rattling sound.
The page saysThat sound is a warning before a strike.
The source saysThe sound serves as a warning before the snake strikes.
The page saysThe National Zoo calls it more docile than other members of its family, and likelier to stay motionless when found.
The source saysthe timber rattlesnake is more docile than other members of its family and is more likely to stay coiled or stretched out, motionless when encountered in the wild
The page saysTimber rattlesnakes range across the eastern half of the United States, from eastern Kansas and Texas to Georgia, the Carolinas and New England, and from New York to northern Florida.
The source saysTheir range extends from eastern Kansas, Texas, Iowa and central Wisconsin to Georgia, the Carolinas, West Virginia, western Virginia, Pennsylvania and New England. Timber rattlesnakes can be found as far north as New York and as far south as northern Florida.
The page saysThey hibernate in crevices on or just under the ground
The source saysIn the winter, they hibernate in crevices found on the ground or slightly underneath.
The page saysThe IUCN rated the species Least Concern in 2007
The source saysAs of a 2007 analysis, timber rattlesnakes are listed as a species of least concernNote: 2007 assessment
The page saysNew Jersey saw a 50 to 66 percent population decline
The source saysin New Jersey the timber rattlesnake experienced a 50-66% population decline
The page saysthe species is regionally extinct in Canada
The source saysThis species is regionally extinct in Canada
The page saysAdults typically measure between 2.5 and 5 feet long (0.76 to 1.5 meters), according to the National Zoo, though some have been reported at up to 7 feet (2 meters).
The source saysAdults typically reach lengths of 2.5-5 feet (.76-1.5 meters), but there are reports of timber rattlesnakes growing up to 7 feet (2 meters) long.Note: FAQ
The page saysA timber rattlesnake that feels threatened raises its body and shakes its tail, knocking the keratin buttons of the rattle into each other.
The source saysWhen threatened, it props itself up and shakes its rattle, which presses the buttons togetherNote: FAQ
The page saysIt sits in the brush, waits for prey to pass, then strikes, bites and injects venom.
The source sayscapture prey by waiting patiently in the brush, and then quickly striking, biting and injecting venom into passing prey
The page saysand in some places they gather in dens under rocks.
The source saysIn other parts of their range, they congregate in dens underneath rocks
The page saysThe National Zoo describes the sound as a warning before the snake strikes.
The source saysThe sound serves as a warning before the snake strikes.Note: FAQ
The page saysFrom Kansas to Florida, and gone from Canada
The source saysThis species is regionally extinct in CanadaNote: heading
The page saysA warning first, then venom
The source saysThe sound serves as a warning before the snake strikes.Note: heading
The page saysTo warn.
The source saysThe sound serves as a warning before the snake strikes.Note: FAQ

Source
02

Animal Diversity Web

Crotalus horridus. Animal Diversity Web.

The page saysThe big eastern pit viper that senses heat, waits in ambush and rattles a warning first
The source saystimber rattlers are pit vipers. This means they have heat sensitive pit organsNote: tagline; ambush and warning below
The page saysHeat-sensing pits between nostril and eye that detect very slight changes in temperature
The source saysheat sensitive pit organs located between the nostrils and the eyes. They are sensitive to radiant energy and can distinguish very slight changes in temperature.Note: stats.superpower
The page saysIt swallows its prey whole once the venom has killed it.
The source saysThe prey is killed when bitten because the snake injects venom. Timber rattlesnakes wait until the animal is dead then swallows prey whole.
The page saysTimber rattlers are pit vipers, with heat-sensitive pit organs between the nostrils and the eyes that can tell very slight changes in temperature apart.
The source saystimber rattlers are pit vipers. This means they have heat sensitive pit organs located between the nostrils and the eyes. They are sensitive to radiant energy and can distinguish very slight changes in temperature.Note: blockquote
The page saysA snake that senses heat
The source saysheat sensitive pit organsNote: heading
The page saysHeat sensor
The source saysheat sensitive pit organsNote: blockquote lead

Source
03

Human Ageing Genomic Resources, AnAge

AnAge entry for Crotalus horridus. Human Ageing Genomic Resources, AnAge.

The page saysAnAge lists an average adult weight of 1,000 grams, about a kilogram.
The source saysAdult weight 1,000 gNote: listed under 'Life history traits (averages)'
The page saysAnAge's maximum longevity figure is 30.2 years, for a snake in captivity.
The source saysMaximum longevity 30.2 years (captivity)
The page saysweightKg: 1
The source saysAdult weight 1,000 gNote: battleStats; Light class

Source
04

New York State Department of Environmental Conservation

Timber Rattlesnake. New York State Department of Environmental Conservation.

The page saysIn New York, where the record is 60 inches, it is the largest venomous snake.
The source saysthe timber rattlesnake is the largest venomous snake in New York. The record length in New York is 60 inches.
The page saysNew York's DEC says an adult's average lifespan may be 15 to 20 years
The source saysonce they reach maturity, the average life span may be between 15 and 20 yearsNote: current DEC page replaces AnAge's 16-22, which cites an older DEC text [0440]
The page saysa new segment is added each time the snake sheds its skin
The source saysA new segment is added to the base of the rattle each time the snake sheds.
The page saysSegments also break off, and a full rattle is rarely seen.
The source saysSnakes with a complete rattle are rarely seen-segments regularly break off during the year.
The page sayssome wild ones are known to have lived beyond 50 years
The source saysindividuals being documented to have lived for more than 50 years in the wildNote: FAQ
The page saysa snake that survives to maturity may live 15 to 20 years on average
The source saysonce they reach maturity, the average life span may be between 15 and 20 yearsNote: FAQ
The page saysJuvenile deaths run very high
The source saysJuvenile mortality is very high
The page sayssome wild snakes have been recorded past 50
The source saysindividuals being documented to have lived for more than 50 years in the wild
The page saysMany die young.
The source saysJuvenile mortality is very highNote: FAQ

Source
05

Rokyta, Wray & Margres 2013

Rokyta, Wray & Margres (2013). The genesis of an exceptionally lethal venom in the timber rattlesnake (Crotalus horridus) revealed through comparative venom-gland transcriptomics. BMC Genomics.

The page saysSome rattlesnake venoms have shifted exceptionally fast.
The source sayssome rattlesnakes have undergone exceptionally rapid, dramatic shifts in the composition, lethality, and pharmacological effects of their venoms
The page saysTimber rattlesnake venom generally causes bleeding (it is hemorrhagic), but populations along the southern edge of the range carry highly lethal, neurotoxic venom instead.
The source saysgenerally has hemorrhagic venom, but populations along the southern edge of their range express highly lethal, neurotoxic venomNote: Discussion
The page saysA 2013 study of one snake from northern Florida found its venom glands made almost none of the two major classes of bleeding toxins.
The source saysalmost complete loss of expression of the two major classes of diverse hemorrhagic toxinsNote: one animal sequenced: 'we sequenced the venom-gland transcriptome of an animal from this population'; population from northern Florida
The page saysThe venom itself varies.
The source saysSuch shifts have occurred within speciesNote: also 'generally has hemorrhagic venom, but populations along the southern edge'

Source
06

Hammerson 2007

Hammerson (2007). Crotalus horridus. The IUCN Red List of Threatened Species 2007: e.T64318A12765920.

The page saysLeast Concern
The source saysIUCN Red List category: Least Concern (LC).Note: conservationStatus; assessed 2007; category read via GBIF copy of the Red List

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.