Snake Cannibalism: An Evolutionary Survival Strategy
A study published on November 2, 2025, in the journal Biological Reviews indicates that cannibalism has evolved independently at least 11 times across various snake lineages throughout evolutionary history. Researchers reviewed 500 reports of cannibalistic behavior across 207 snake species to reach this conclusion.
Scientists propose that cannibalism, while perceived as uncommon in humans, can be a beneficial and strategic behavior for snakes, often emerging as an opportunistic dietary choice or in response to environmental stressors such as limited resource availability.
A Widespread and Adaptive Strategy
The behavior is widespread across the animal kingdom and has been hypothesized to aid in brood size control, population control, or opportunistic predation. This comprehensive research gathered 503 documented cases of cannibalism from snake groups across all continents where snakes are found, encompassing both wild and captive populations.
Family-Specific Observations
The study highlighted varying prevalence and contexts for cannibalism across different snake families:
- The Colubridae family accounted for 29% of reports, with many cases potentially linked to food scarcity.
- Viperidae (vipers) represented 21% of reports, mostly observed in captivity and potentially influenced by confinement stressors.
- Elapidae (cobras), known for preying on other snakes, accounted for approximately 19% of the reports.
Key Factors: Diet and Jaw Structure
The study also noted that almost half of the cannibalistic snake species have generalist diets, suggesting a correlation between dietary flexibility and cannibalistic behavior when necessary.
A key physical factor identified for cannibalism is the snake's jaw structure. Jaws must be capable of opening wide enough to consume another snake; no reports of cannibalism were found in species lacking this ability.
This comprehensive review provides a significant overview of cannibalism in snakes, highlighting its repeated independent evolution and suggesting it as an adaptive strategy for survival in diverse circumstances.