Yes, female Booted Eagles, also known as Golden Eagles, are indeed bigger than their male counterparts. This size difference is a unique characteristic of the species, known as “reversed size dimorphism.”
The Size Difference Between Male and Female Booted Eagles
The size difference between male and female Booted Eagles is quite significant. In the UK, for example, the average male Golden Eagle weighs 3.7kg and has a wingspan of 2.0m, while the female weighs 5.2kg and has a wingspan of 2.2m. This size difference is not limited to the UK population but is a common trait across the species’ wide distribution in the northern hemisphere.
The size difference between male and female Booted Eagles extends beyond just weight and wingspan. A study of 126 eagles in 1932 found that the average body length for males was 226 cm (7 ft 5 in), while for females it was 274 cm (9 ft 0 in). Another sample from the Nullarbor Plain showed that males averaged 3.13 kg (6.9 lb) in body mass and 193 cm (6 ft 4 in) in wingspan, while females averaged 3.8 kg (8.4 lb) in body mass and 212 cm (6 ft 11 in) in wingspan.
Implications of the Size Difference
Image source: Booted eagle By Dr. Raju Kasambe
The size difference between male and female Booted Eagles has implications for their behavior and ecology. The larger size of females may give them an advantage in hunting larger prey, which could explain why they are known to attack fully grown goats, deer, and even wolves. However, the most common prey for Golden Eagles are smaller mammals.
Factors Contributing to the Size Difference
The reasons behind the reversed size dimorphism in Booted Eagles are not fully understood, but several factors may contribute to this phenomenon:
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Hunting Strategies: The larger size of female Booted Eagles may allow them to hunt larger prey, which could provide them with a competitive advantage over their male counterparts.
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Nesting and Breeding: The larger size of females may be advantageous for nesting and breeding, as they may be able to better protect their eggs and young from predators.
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Sexual Selection: The size difference may be the result of sexual selection, where females prefer to mate with larger males, leading to the evolution of larger females over time.
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Ecological Factors: The specific environmental conditions and resource availability in the Booted Eagles’ habitat may favor the larger size of females, leading to the development of this unique size dimorphism.
Conclusion
In summary, female Booted Eagles, also known as Golden Eagles, are indeed significantly larger than their male counterparts. This size difference, known as “reversed size dimorphism,” is a unique characteristic of the species and has implications for their behavior and ecology. The reasons behind this phenomenon are not fully understood, but factors such as hunting strategies, nesting and breeding, sexual selection, and ecological factors may all play a role in the development of this size difference.
References:
– https://www.earthandanimals.com/animal_encyclopedia/params/category/173340/item/994217/
– https://en.wikipedia.org/wiki/Golden_eagle
– https://www.discoverwildlife.com/animal-facts/birds/facts-about-golden-eagles
– https://en.wikipedia.org/wiki/Wedge-tailed_eagle
– https://europeanraptors.org/golden-eagle/
