Credit: Paul Irish



Timber Rattlesnake (Crotalus horridus)



I. Physical Characteristics

a. Size

i. Length between 3 and 4½ feet
ii. Stocky build - thick bodied
iii. Triangular head
iv. Rigid scales - lend to rough appearance
v. Largest venomous snake in New York

b. Markings - generally the same for adults and juveniles

i. Yellow phase

1. Light background in yellow, brown, or gray
2. Black or dark brown crossbands

ii. Black phase

1. Dark background
2. Black or dark brown crossbands

c. Unique characteristics

i. Temperature sensitive pit

1. Sensory organ
2. Detect prey and potential predators

ii. Rattle
1. Composed of loosely attached hollow scales
2. New fragment added each time it sheds
3. Rattle frequently breaks

iii. No external or internal ear openings
1. Virtually deaf
2. Rely upon feeling ground vibrations

iv. Forked tongue

1. Helps them smell
2. Odors are picked up by the tongue
3. Tongue is inserted into Jacobson's Organ at the roof of the mouth

v. Poikilotherms - temperature of their body changes with that of their outside environment
vi. Shedding of skin - every 1 to 2 years
vii. Elongated organs to accommodate body shape

II. Habitat and Lifestyle

a. Prefer rocky, hilly areas of sun in deciduous forests in the summer
b. Hibernation - in winter

i. Rocky dens
ii. Return to the same den and nesting sites yearly using scent
iii. Gather with other timber rattlesnakes, as well as with other venomous snakes to hibernate
iv. Emerge sluggishly in mid-May

c. Live between 16 and 22 years

III. Reproduction

a. Sexually maturity

i. Males - 5 years
ii. Females - 7 to 11 years

b. Breeding usually in early spring and fall

i. Males use pheromones to attract females
ii. Females

1. Pregnant females called "gravid"
2. Gestation period between 4 and 5 months
3. Give birth

a. Usually 9, though 4 to 14, babies
b. Every 3 to 5 years
c. Post-birth young

i. Each emerges individually in its own sac
ii. 1 foot long
iii. Possess:

1. Venom
2. Hollow fangs
3. Small rattle - "button"

iii. Return to same nesting den

IV. Food

a. Don't eat during hibernation
b. Hunt and feed less than twenty times during the summer
c. Usually hunt at night
d. Most common foods

i. Rodents - mice and rats
ii. Shrews
iii. Chipmunks
iv. Squirrels
v. Rabbits
vi. Other similar sized mammals

V. Decline

a. Human intervention

i. Killing out of fear
ii. Illegal sales
iii. Illegal collection

b. Statistics

i. 26% New York dens are extinct
ii. 60% reduction in population since 1900

VI. Preventing extinction

a. Legislation

i. New York Status - Threatened
ii. Federal Status - not listed

b. Habitat preservation

i. Being ecologically mindful
ii. Example: Central Hudson Gas and Electric

c. Field surveys - collect data to preserve species

i. Mark and recapture
ii. Radio telemetry techniques

VII. Where to find them locally

a. Southeastern New York (Hudson River Valley)
b. Fishkill Ridge Conservation Area
c. Many New York State Parks

(Specific information is not generally given as to protect the species from harm, especially 'collection.')