The Northern Pacific Rattlesnake is a venomous snake belonging to the Viperidae family. It is also known as Pacific Rattlesnake, Diamond-Back Rattlesnake, Missouri Rattlesnake, Oregon Rattlesnake or its scientific name Crotalus Oreganus.

Currently there are 5 subspecies of Crotalus Oreganus:

  • C. o. Oreganus
  • C. o. Caliginis
  • C. o. Helleri
  • C. o. Concolor
  • C. o. Lutosus


The main color of the Northern Pacific Rattlesnake varies from brown to dark gray, olive green, pale yellow or black. Its dorsal scales have many irregular dark brown spots. In older specimens, these spots are bordered by a light color.

These irregular spots are also found on the lateral parts of its body. The ventral scales are beige or cream, always with brown spots. Its dorsal scales are carinated.

Its head is large, which makes it easy to distinguish from the neck. It has a large dark spot on the top bordered with light. Its eyes are small with vertical elliptical pupils. A large dark stripe starts from the back of her eyes to the corner of the jaw. There is also a very large dark stripe that runs from under its eyes to the sides of Its head. Its snout is rounded.

Between its nostrils and its eyes are the thermoreceptors, small sensors able to detect the temperature variations around him. This allows it to detect its warm-blooded prey.

Its body ends in a small cone-shaped tail on which is the famous rattle characteristic of Pit Vipers. The last two rings of the tail (starting from the base of the tail) are often darker in color than the others.

Its fangs are quite long and mobile. When it opens its mouth, they are positioned vertically and retract backwards when it closes its mouth.

Northern Pacific Rattlesnake Size

Depending on the geographical area of the specimen, the length of the Northern Pacific Rattlesnake can vary greatly. Its size ranges from 2ft to 5ft (60cm to 150cm), with an average of 2.6ft (80cm). Currently, the largest measured specimen of this species was 5.4ft (165cm).


The Northern Pacific Rattlesnake is both diurnal and nocturnal. In autumn and spring, it is mainly active during the day, while it will become more active at night during the hot summer days. In winter, this snake hibernates. Its hibernation period will be more or less long depending on the altitude at which it lives.

Like all rattlesnakes, it is equipped with heat-sensitive dimples that allow it to detect its prey. Before attacking, this reptile rolls up on itself and then suddenly leaps on its prey. It then injects its venom to immobilize it and help it digest.

➤ We have written an article on snake venom if you would like to learn more about its effects.

The Northern Pacific Rattlesnake is moderately aggressive. Before attacking, it will show its displeasure by vibrating its rattle.


The venom of the Northern Pacific Rattlesnake is extremely toxic. It consists of a toxin similar to that of the Mojave Rattlesnake which causes nervous system dysfunction. It also has small doses of myotoxic and hemotoxic substances.

Local symptoms associated with a Northern Pacific Rattlesnake bite include severe pain, severe swelling, blistering, bruising and in some cases necrosis.

General symptoms include abdominal pain, nausea, vomiting, diarrhea, headache, dizziness and convulsions.

Currently, the mortality rate of Crotalus Oreganus bites is still unknown.

Northern Pacific Rattlesnake Bite Treatment

If you are bitten by a Northern Pacific Rattlesnake, you should immediately go to the hospital.

While waiting for medical help, start by removing objects that may be compressing the affected limb to limit damage. Try to immobilize the limb to limit infection.

Also, avoid applying creams or ointments to the wound. Do not cut the wound or suck out the venom.

The few bites that have been recorded so far have occurred as a result of handling the animal

At this time, there are two antivenoms that work against the poison of the Northern Pacific Rattlesnake.


The Northern Pacific Rattlesnake lives in several northwestern states of the United States as well as southern British Columbia and parts of Canada.

In the United States, it lives in Washington, California, Nevada, Utah, Arizona, Oregon, southern and western Idaho and western New Mexico.

It is also found in northern Mexico, Baja California and extreme northern Baja California.

This Rattlesnake likes dry and rocky places. It also lives in the high plains, in the hills or on the plateaus.

In summer, it is possible to see it in open meadows or basking in the sun on rocks. In winter, it prefers to hide under stones or in natural caves.

It can be found up to 8200ft (2500m) above sea level.

What do Northern Pacific Rattlesnakes eat ?

The diet of the Crotalus Oreganus consists mainly of small mammals (mice, squirrels, rabbits), eggs, birds, amphibians or lizards.

The juveniles will be satisfied with small insects.


Like all members of the genus Crotalus, the Northern Pacific Rattlesnake is an ovoviviparous snake. This means that the babies are born in the body of the female and the latter are born directly alive.

The mating season is between August and early September. After mating, the female stores sperm until late winter to ensure that fertilization will take place in the spring.

Once pregnant, the female no longer feeds and remains near her den until she gives birth. This period can last up to 19 months. The babies are born 13 to 14 months after mating.

A brood consists of an average of 5 babies, although it can go up to 20.

After the birth, the female goes directly back to hibernation. The babies will wait for their first moult to hibernate in their turn.

The reproduction takes place every 2 to 3 years in this species, notably because of the long period of youth of the female which must recover its weight before reproducing again.

The sexual maturity is reached around 3 to 4 years for a male, the double for a female.


According to the IUCN red list, the status of the Northern Pacific Rattlesnake is of concern in terms of its risk of extinction. This is mainly due to their wide range and the number of specimens within this population.

The main threats to this species are agriculture, grazing, and construction that reduce its habitat area. The reduction in the number of prey in their natural environment is also a problem.

Humans remains a formidable predator for them as many kill these reptiles out of fear, which reduces the population considerably.

However, Crotalus Oreganus is considered vulnerable, and therefore partially protected under the British Columbia Wildlife Act.


There you have it, you now know everything about the Northern Pacific Rattlesnake. If you liked this article, don’t hesitate to subscribe to our Newsletter to be informed of our new articles.

Passionate about snakes ? You should go visit our online store. Snake Lounge™ is the first brand entirely inspired by the snake in the creation of its products. Through our Jewelry, Clothing and Accessories, our goal is to transcribe our passion for this animal while giving it a positive image. Our high quality products combine elegance, symbolism and express the will to differentiate ourselves.

Snake Lounge
    Your Cart
    Your cart is emptyReturn to Shop
      Calculate Shipping
      Apply Coupon
      Available Coupons
      reduc5 Get 5% off