You’re out hiking in the woods, and you come across a medium-sized snake with a mottled pattern. This snake begins hissing at you and shaking its tail. Naturally, you think, “rattlesnake.” But did you know there’s another type of snake that behaves this way? The bull snake is often mistaken for the rattlesnake because of its behavior and similar patterning. In this article, we’ll compare the rattlesnake vs. the bull snake so you can learn to tell them apart.
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How Can You Tell a Rattlesnake from a Bull Snake?
Rattlesnakes are very different from bull snakes; but, at first glance, you may have a hard time telling them apart–especially when it comes to their behavior when threatened. Let’s take a look at each snake in turn, then discuss some of their similarities and differences.
Rattlesnake
Rattlesnakes are venomous pit vipers found throughout the United States. There are about 32 different species of rattlesnake in all.
Most rattlesnakes have mottled patterns and are brown and gray in color, and each one has a distinctive light-colored rattle on its tail. Rattlesnakes generally grow 3 to 6 feet long, though some species can grow up to 8 feet long.
These venomous snakes hunt a variety of small animals, especially rodents, lizards, frogs, and insects. They hunt by killing prey with venom; the sunken pits behind their nostrils allow them to sense the body heat of their prey and strike with great accuracy.
Bull Snake
Bull snakes are nonvenomous constrictors found throughout much of the southern and western regions of the United States. They are a single species of snake and have no subspecies.
Bull snakes are generally black or gray and beige in color, but they have similar mottled patterns with rattlesnakes, which is what frequently leads to their misidentification.
According to Britannica, bull snakes can grow up to 8 feet long. They will hiss and shake their tail when threatened, which also gives them the appearance of rattlesnakes to the untrained observer.
Bull snakes primarily hunt small rodents, though they also eat a lot of birds and lizards. They kill prey by crushing and suffocating them.
Similarities and Differences
As you may have noticed from the preceding paragraphs, rattlesnakes and bull snakes have some obvious similarities and differences. Let’s go through and take a closer look at these.
The similarities:
- Colors and patterns: Rattlers typically have more muted colors than bull snakes, but their patterns are strikingly similar. Some bull snakes have more pale coloring, which can further lead to their being confused with rattlesnakes.
- Posturing and behavior: Both rattlesnakes and bull snakes tend to move in an S-shaped pattern and will take on an S-shaped coil when frightened. Both snakes will hiss and shake their tails when they sense a threat.
- Distribution and habitat: Rattlesnakes are found throughout the U.S. and other parts of North America. Bull snakes are not quite as widely distributed, but they are found especially in the south and west, where rattlesnakes are extremely common.
- Head shape: Rattlesnakes have the classic pit viper triangular head. Bull snakes have pointed snouts that allow them to dig more easily, giving their head a more triangular appearance–though not as noticeable as a rattlesnake’s head.
- Size: Bull snakes and rattlesnakes are similar in size and build–both snakes have thick, strong bodies. That said, bull snakes may get somewhat larger than some species of rattlesnakes.
The differences:
- The eyes: Rattlesnakes have dragon-like eyes with long, narrow, slit-like pupils. Bull snakes have rounded eyes with dark, round pupils.
- The tails: Rattlesnakes have a distinctive and highly recognizable rattle on their tails. Bull snakes may shake their tails around when they are frightened, but they do not have this rattle; instead, the mottled pattern over most of their body gives way to bands or stripes at the tail.
- Rattlesnakes are venomous, bull snakes are not: This is perhaps the biggest and most important difference. Bull snakes cannot poison their victim with venom as rattlesnakes can; instead, they will wrap themselves around their prey and suffocate it.
- Bull snakes dig burrows, rattlesnakes do not: Rattlesnakes spend a lot of time in dens, especially in the winter, but they don’t make these dens themselves as they are unable to dig. Bull snakes, on the other hand, are proficient diggers and burrowers, and they will dig their own dens.
- Rattlesnakes give birth to live young, bull snakes lay eggs: Rattlesnakes, like other pit vipers, give birth to live babies because their eggs hatch while still inside the mother. Bull snakes, like most nonvenomous snakes, lay eggs that hatch after being laid.
Check out this video for a good visual comparison of the two types of snakes:
Do Bull Snakes Kill Rattlesnakes?
One common misconception is that bull snakes eat rattlesnakes and kill them for sport–that keeping bull snakes around will keep rattlesnakes away. This is not necessarily true though.
Bull snakes can kill rattlesnakes, but they don’t necessarily do it for sport. They typically do it because they sometimes have to compete for food sources.
Both rattlers and bull snakes are fairly non-confrontational, but if both are stalking the same prey or competing for food during shortages, they may fight each other. In these cases, the bull snake might win, or the rattlesnake might win–these snakes are evenly matched, but for different reasons.
Bull snakes are about the same size but may grow slightly larger than rattlesnakes. As noted above, they are constrictors, so they can kill rattlesnakes by wrapping around and suffocating them.
Rattlesnakes, however, could also kill bull snakes by biting and injecting their venom into them. So if a rattlesnake is able to bite a bull snake before the bull snake suffocates it, the rattlesnake would likely win the battle.
Do Rattlesnakes Breed with Bull Snakes?
This is another common misconception. Bull snakes and rattlesnakes may look similar, but are much different from each other; therefore, they are unable to breed with each other.
Rattlesnakes belong to the Viperidae family, while bull snakes belong to the Colubridae family. These snake families contain too many genetic differences, so they cannot cross-breed.
Even if they tried to mate, a bull snake and a rattlesnake would not be able to produce young. Again, their many genetic differences are responsible for this.
Rattlesnake Vs Bull Snake: Which Bite Kills Fastest?
Rattlesnakes are venomous, while bull snakes are not. That said, a bite from a bull snake can still do damage if not treated promptly and appropriately.
Rattlesnakes inject venom into their victims, a venom which can cause unpleasant symptoms as well as widespread blood and tissue damage over a period of hours to days. If left untreated, a rattlesnake bite can kill a healthy adult within a few days.
Bull snakes have no venom, but their mouths are full of bacteria. Their bites can cause serious bacterial infections; if left untreated, these infections can lead to blood poisoning which may kill a human over a period of several days.
Of the two, rattlesnake bites are much more deadly and will kill more quickly than bull snake bites.
That said, both rattlesnake and bull snake bites can be treated quite effectively, and if you receive the proper medical care, you should be able to recover fully regardless of the type of snake that bit you.
Conclusion
On first glance, rattlesnakes and bull snakes look and behave quite similarly. But, upon closer inspection, you will find that these two types of snakes have many characteristics that set them apart from each other.
Bull snakes also get into hen houses and eat eggs, just saw a 6 foot one yesterday. Never seen rattlers do that. Don’t kill the hens though. Oklahoma
Bull snakes can climb trees. Hence they sometimes eat birds or eggs. I have never heard of a rattlesnake climbing trees.
The timber rattlers in Montana climb trees.
We only have Western diamondback (aka prairie) rattlesnakes in Montana…
I didn’t think the timber rattler’s range went that far West.. Normally one thinks of Minnesota as the farthest west for this snake.
I have read the article and agree with the content but two questions remain.
First, how did bull snakes develop this immunity to rattlesnake venom, and why? The odds that they just were created this way are unlikely. The exposure to the Rattlesnake venom is required to make this happen.
Any self-respecting Biology student understands the theory of natural selection. Environmental pressure and other pressures create the need and an opportunity for evolution. So the theory is that close contact and most likely fighting to the death between these species is the pressure and the opportunity. It seems obvious that the immunity was developed through close encounters long before humans were here. So at some point there was repeated close contact between the species and likely death on both sides until the Bull Snakes developed the immunity we see today. That is in plain English they likely killed each other when they crossed paths. This does not mean they hunted each other. It does not mean they would eat the loser either. It is just a conflict between two species that likely competed for the same niche before humans were here. The different activity windows for these species are likely a reaction to that competition as well. So anyone who says Bull snakes don’t kill rattlers is just an opinion that does not take into account the accepted role and process of natural selection. Just because you haven’t seen it does not mean it did not happen. If it no longer happens that does not mean it did not happen in the past.