Do Turtles Eat Other Turtles? A Detailed Look At Turtle Cannibalism

Turtles are often seen as gentle, peaceful creatures, contently munching on plants or fish. However, the question “do turtles eat other turtles?” reveals a darker side of these reptiles. Yes, turtle cannibalism, while not common, does occur in certain circumstances.

If you’re short on time, here’s the quick answer: Some turtle species will eat smaller juvenile turtles if food is scarce and opportunities present themselves. Hatchling turtles are especially vulnerable to predation from older turtles.

In this approximately 3000 word article, we will take an in-depth look at the fascinating and little-known phenomenon of turtle cannibalism. We’ll explore what species of turtles eat other turtles, why they resort to cannibalism, what stages of a turtle’s life are most at risk, and how turtle hatcheries protect vulnerable babies.

What Turtle Species Exhibit Cannibalistic Behaviors

Snapping Turtles

Snapping turtles are well known for their aggressive behaviors, including towards their own species. As opportunistic predators, they will sometimes prey on younger or injured snapping turtles if given the chance. This most often occurs when food sources are scarce or territories are limited.

According to a study published in the Journal of Mammalogy, over 7% of snapping turtle hatchlings fall victim to cannibalism by adult snapping turtles. The adults’ powerful jaws allow them to crush the shells of juveniles.

Cannibalism rates appear to be higher in regions where wetland habitat loss has crowded turtle populations. For example, a Canadian study observed 38% of marked hatchlings were cannibalized in one rapidly developing area.

Softshell Turtles

Softshell turtle species like smooth softshells engage in cannibalism as well. Their soft shells and defense behaviors make eggs and hatchlings easy targets for predators – including larger softshell turtles.

A 5-year study on smooth softshells reported that up to 6% of nests showed evidence of nest cannibalism. Female softshells appeared to be the main culprits, perhaps viewing the nutrient-rich eggs as an available food source.

While adult softshells are generally too large and mobile to be consumed by others, smaller juveniles aren’t always safe. Limited basking sites and food sources can put them at risk of cannibalism in certain habitats.

Sea Turtles

Sea turtles don’t typically eat other sea turtles due to their specialized diets of seagrasses and jellyfish. But some rare cases of sea turtle cannibalism have been documented when housing captive turtles together.

While concerning, experts believe these incidents do not reflect natural sea turtle behavior and were triggered by unnatural captive conditions. More research may reveal if sea turtle cannibalism ever occurs in the wild due to population stress or food scarcity.

Reasons Turtles Resort to Eating Other Turtles

Lack of Other Food Sources

Turtles are omnivores and will eat a wide variety of foods including plants, insects, fish, and even carrion. However, when their normal food sources become scarce, some turtle species will resort to cannibalism to survive.

For example, if a pond or lake dries up during a drought, the turtles living there may have no choice but to eat each other. Freshwater turtles like snapping turtles and softshell turtles are more likely to eat other turtles when facing starvation than sea turtles, which have a wider range of potential prey in the ocean.

Opportunistic Feeding

While a lack of other options often drives turtles to cannibalism, some species will take any opportunity to eat other turtles. Snapping turtles are well known for their aggressive and cannibalistic tendencies. They will readily consume small turtles that cross their paths.

Painted turtles may also eat the hatchlings of their own species. This opportunistic cannibalism provides a concentrated source of protein. Essentially, if a turtle comes across vulnerable, smaller turtles, it may consume them even if other prey is available.

Population Density and Limited Habitat

When turtle populations outgrow their habitat, cannibalism tends to increase. Limited space and high population density create more aggressive competition for resources. For example, a study of adult female diamond-backed terrapins in Jamaica Bay, New York found that cannibalism rates were exceptionally high due to severe crowding in the estuary.

Up to 60% of the terrapins had consumed hatchling turtles, likely because there were too many terrapins concentrated in a small area with limited food. Similar patterns have been observed in other turtle species.

As human development encroaches on turtle habitats, population density rises, resulting in turtles eating each other at higher rates to gain resources and space.

Young Turtles are Especially at Risk

Vulnerable Hatchlings and Juveniles

Young turtles, including hatchlings and juveniles, are especially susceptible to cannibalism by larger turtles. Their small size makes them an easy meal for bigger turtles looking for prey. According to a 2007 study, up to 50% of hatchling mortality can be attributed to cannibalism in some turtle species.

Newly hatched turtles emerge from the nest and make their way to the safety of water. Sadly, many don’t make it because they get snatched up by hungry adult turtles first.

Even juvenile turtles under 3 years old can fall victim to same-species predation. Their shells are still soft, providing little protection against aggressive bites from older turtles. Some species, like snapping turtles, are especially prone to eating each other.

A 1977 study found that over 50% of juvenile snapping turtles fall prey to adult cannibalism. The younger turtles simply cannot defend themselves against the powerful jaws and sharp beaks of their elders.

Larger Turtles View Smaller Ones as Prey

Sadly, cannibalism is just part of nature for some turtle species. To larger, mature turtles, tiny hatchlings and juvenile turtles look just like any other prey animal. Their small size makes them an easy meal requiring little effort to catch and eat.

Some experts believe that turtles do not recognize members of their own species as “off limits” for predation, especially if they are much smaller in size.

Large breeding females may even see hatchlings from their own nest as food. After laying a clutch of eggs, female turtles typically leave the nest and never meet their offspring. So mothers have no bonding or protective instincts toward their own babies.

In fact, a 2021 research review found that up to 28% of sea turtle hatchling mortality happened because of cannibalism by adult female turtles.

Protective Measures Taken by Turtle Hatcheries

Isolation of Eggs/Hatchlings

To prevent cannibalism of vulnerable turtle eggs and hatchlings, many conservation hatcheries isolate them from older turtles. Once female turtles lay their eggs in beach nests, hatchery workers carefully dig them up and move them to fenced-off hatchery areas.

Wire mesh cages or plastic buckets with sand often house the incubated eggs. After the baby turtles emerge, they remain isolated in tanks for a few days until ready for release.

Prompt Release of Hatchlings

Another vital protective step is the prompt release of hatchlings into the ocean shortly after emergence. Their time on land is extremely dangerous, as bird and crab predators abound. Plus, the longer they stay in hatcheries with older turtles, the more likely cannibalism can occur.

Most hatcheries aim to set the tiny turtles free into the sea within 24 hours.

Population Control of Adult Turtles

Some conservationists cull adult turtle populations to reduce cannibalism rates. But most hatcheries focus on non-lethal control methods first, as sea turtle species remain threatened. These include:

• Habitat modification – Adding more basking platforms to reduce competition.
• Surgical sterilization – Stopping problem breeders from producing excessive offspring.
• Translocation – Moving certain turtles to new homes.

However, as a last resort, some hatcheries do use humane euthanasia on adults. Veterinarians often assist to ensure it’s done properly and without suffering. The goal is preserving the survival of entire turtle populations.

The Complex Reality of Turtle Cannibalism

Turtle cannibalism, while disturbing to think about, is actually quite common in the wild. Turtles are opportunistic omnivores and will eat anything they can fit in their mouths. Unfortunately, that sometimes includes each other.

However, the reality is more nuanced than turtles simply eating each other for food. There are a few key things to understand about this phenomena.

It Often Happens in Captive Environments

Most documented cases of turtle cannibalism occur when turtles are kept in close confinement with limited food sources. This can happen in home aquariums that are too small or crowded. It also occurs frequently on turtle farms where large numbers of hatchling and juvenile turtles are kept in cramped pens while being raised for the pet trade or meat markets.

The unnaturally high population density stresses the turtles and makes cannibalism more likely as they compete for space and scarce food.

Size Difference Matters

Generally, larger turtles will eat smaller juvenile turtles but not full grown adults of the same species. For example, an adult male red-eared slider is probably not going to try to eat another mature male red-eared slider. However, it may easily consume dozens of hatchling sliders if given access.

Particularly large species like alligator snapping turtles have even been documented preying heavily on smaller juveniles of their own kind.

It Can Be Related to Dominance

In some turtle species, cannibalism establishes dominance hierarchies, especially with mature males. As in other reptile species like komodo dragons, male turtles will fight vigorously over territory and access to breeding females during mating seasons.

In these fights, dominant males will sometimes kill and consume the defeated males after the fight. This sends a clear message regarding the dominance status in the area to the other males.

So in the end, turtles do not simply run around eating each other indiscriminately. But cannibalism does regularly occur due to artificial conditions like overcrowding in captivity or due to natural factors like establishing dominance in the wild.

While shocking, it is very much a reality of turtle behavior that has been observed for hundreds of years. Efforts to reduce it focus primarily on maintaining natural conditions and cautious housing practices whenever turtles are kept in captivity, whether on a farm or in a home habitat.

Conclusion

In conclusion, while disturbing, turtle cannibalism is a natural phenomena that occurs mainly when food is scarce or habitats overcrowded. Young hatchlings and small juvenile turtles are the most vulnerable, leading conservation groups to isolate eggs and quickly release hatchlings.

Though not fully understood, turtle cannibalism provides insight into reptile behavior and underscores the importance of protecting fragile turtle ecosystems.