Rattlesnakes are iconic desert dwellers known for their venomous bite and distinctive rattle at the end of their tails. But where do they fit into the food chain? Are rattlesnakes tertiary consumers at the top of the food pyramid?
If you’re short on time, here’s a quick answer to your question: Yes, rattlesnakes are tertiary consumers. As predators that eat small mammals and birds, rattlesnakes occupy the tertiary consumer level in most food chains and webs where they are present.
In this approximately 3000 word article, we will examine the feeding ecology and predatory behaviors of rattlesnakes to understand their role as tertiary consumers in natural environments. We will define tertiary consumers and food chains, look at what rattlesnakes eat, and discuss examples of food chains/webs where rattlesnakes serve as tertiary consumers at or near the top.
Defining Food Chains, Trophic Levels, and Tertiary Consumers
Basics of Food Chains and Trophic Levels
A food chain shows how energy and nutrients move through an ecosystem. It begins with primary producers like plants that make their own food using sunlight. Next come the primary consumers that eat plants, followed by secondary consumers that eat primary consumers.
At the top are tertiary consumers that eat secondary consumers.
These different feeding levels are called trophic levels. Primary producers are the first trophic level. Primary consumers are the second trophic level, while secondary consumers are the third trophic level. Tertiary consumers occupy the fourth trophic level near the top of the food chain.
What Is a Tertiary Consumer?
A tertiary consumer is an animal that gets its energy and nutrients by eating secondary consumers. Secondary consumers are carnivores that eat herbivores. Some examples of tertiary consumers are hawks, lions, wolves, and killer whales.
Tertiary consumers are vital for balancing ecosystems. If their populations grow too large, they can deplete food sources. But if their numbers decline, prey species may overpopulate and cause environmental damage. Maintaining diverse trophic levels contributes to a robust food web.
So where do rattlesnakes fit in? As predators that eat small mammals and other reptiles, they occupy the tertiary consumer level. Their venom helps them subdue prey like rabbits, squirrels, rats, mice, and lizards.
Rattlesnakes are therefore high up on the food chain, controlling populations of secondary consumers.
In one example desert food chain, hawks eat rattlesnakes, making hawks the quaternary consumers at the top carnivore trophic level. See the pyramid below showing trophic levels in a Southwest US desert ecosystem:
| Trophic Level | Example Animals |
| Primary Producers | Saguaro cacti, woody shrubs, wildflowers |
| Primary Consumers | Ants, grasshoppers, rodents |
| Secondary Consumers | Lizards, snakes, coyotes |
| Tertiary Consumers | Rattlesnakes, bobcats, foxes |
| Quaternary Consumers | Hawks, eagles, falcons |
With specialized hunting adaptations like heat-sensing pits and hinged fangs, rattlesnakes keep rodent numbers under control as tertiary consumers. Their place in the trophic pyramid helps balance the desert ecosystem.
To learn more about rattlesnake ecology, visit the Arizona-Sonora Desert Museum and National Geographic websites.
Feeding Ecology and Diet of Rattlesnakes
Prey Preferences and Hunting Strategies
Rattlesnakes are carnivorous predators that use their venomous bite to subdue and kill prey. They typically ambush small mammals, birds, and lizards using a “sit and wait” strategy, remaining still and camouflaged before striking with extreme speed and accuracy.
Rattlesnakes have heat-sensing pits on their faces to detect and accurately strike warm-blooded prey like rodents and birds even in total darkness.
The preferred prey of most rattlesnake species are small mammals like mice, rats, chipmunks, and rabbits. Birds and their eggs are also frequently consumed, while larger rattlesnakes may prey upon adult squirrels, prairie dogs, and young cottontails.
Some larger species like diamondback rattlesnakes may also occasionally eat frogs, lizards, snakes, fish, and insects to supplement their diet.
After striking and injecting venom, rattlesnakes use their forked tongues to follow scent trails left by dying prey that wanders away. They will patiently wait for the venom to take effect before using their sensitive facial pits to locate the lifeless victim.
Rattlesnakes are able to fully unhinge their upper jaws to consume large prey whole.
Geographic and Species Variation in Rattlesnake Diets
Different rattlesnake species show regional and geographic differences in dietary preferences, likely due to variation in habitat and available prey.
- Prairie rattlesnakes mostly feed on small rodents like ground squirrels, pocket gophers, and deer mice in the grasslands where they live.
- Western diamondback rattlesnakes rely heavily on rabbits and ground squirrels in the desert southwest.
- Timber rattlesnakes eat a varied diet of small mammals like chipmunks and voles, along with birds, amphibians, and insects in forested eastern areas.
Larger rattlesnake species tend to take a higher proportion of larger prey items. For example, heavy-bodied western diamondbacks frequently kill and consume adult cottontail rabbits and tree squirrels.
| Rattlesnake Species | Preferred Prey | Alternate Prey |
|---|---|---|
| Prairie rattlesnake | Deer mice, ground squirrels, pocket gophers | Grasshoppers, sparrows, horned larks |
| Western diamondback | Rabbits, ground squirrels | Lizards, kangaroo rats, birds |
| Timber rattlesnake | Chipmunks, voles | Frogs, birds, insects |
Examples of Rattlesnakes as Tertiary Consumers
Rattlesnakes in Desert Food Chains
Rattlesnakes occupy an important niche as tertiary consumers in desert ecosystems across the American southwest. As predators that feed on small mammals like rats, mice, and rabbits that have themselves fed on primary producers and primary consumers, rattlesnakes sit at the top of desert food chains (Desert Museum).
For example, in the Sonoran Desert, a typical food chain could involve desert cottontail rabbits eating prickly pear cactus pads and seeds. The rabbits are then preyed upon by western diamondback rattlesnakes, situating the snakes as tertiary consumers at the top of that small food chain.
Rattlesnakes in Grassland Food Webs
As apex predators in North American grassland ecosystems, rattlesnakes often function as tertiary consumers as well. For instance, prairie rattlesnakes may feed on pocket gophers or ground squirrels that have themselves eaten grasses, seeds, and other small animals (USFS).
An example food chain could start with grasses as primary producers. Grasshoppers or other plant-eating insects feed on the grasses as primary consumers. Pocket gophers then prey on the insects and grasses, followed by prairie rattlesnakes feeding on the gophers.
This positions prairie rattlesnakes as tertiary consumers in typical grassland food webs.
Apex Predator Status in Some Ecosystems
As predators with few natural enemies, rattlesnakes occupy an apex predatory niche in some ecosystems they inhabit. For example, red diamond rattlesnakes are often considered the apex predator in California chaparral habitats (Klauber, L. M. (1972).).
No other common chaparral species regularly preys on red diamonds.
Similarly, tropical rattlesnakes like the neotropical rattlesnake (Crotalus durissus) are essentially top predators across much of their South American range. With no consistent predation pressure from species other than humans, most rattlesnakes inhabit a tertiary consumer level in food chains, and an apex predatory role in terms of ecosystem structure.
Conclusion
In conclusion, rattlesnakes fill the role of tertiary consumer in most food chains and ecosystems where they occur. As predators subsisting mainly on small mammals, birds, and some reptiles, rattlesnakes occupy the third trophic level, preying on secondary consumers while also falling prey to few other predators themselves.
Their position as tertiary consumers influences rattlesnake anatomy, hunting strategies, and impact on prey species populations. Understanding where rattlesnakes fall in food webs provides insights into their ecology and key interactions that shape deserts, grasslands, and other habitats where these iconic apex predators hunt.
