It is relatively easy to distinguish between male and female orcas when observing a pod. Generally, males are longer and bulkier than females, with an average length of 7.5 meters compared to 6.5 meters for females.
However, the clearest form of identification is through the dorsal fin. While males have a straight fin that can reach nearly two meters in height, females have a curved fin that rarely exceeds ninety centimeters. The dorsal fins often have marks and scars on the trailing edge.
Based on these characteristics, one can clearly identify one animal from another. Another method of identification is the white patch (saddle) on the back, located behind the dorsal fin of orcas. This patch is unique to each individual. Scientists can use the notches on the dorsal fin and the saddle to identify an animal and create a comprehensive catalog of the orcas in the area, enabling year-to-year tracking. To facilitate this task, scientists often give names to the orcas they study.
The challenge usually arises with juveniles, where the saddle has a duller tone and the fin remains curved, resembling the dorsal fins of females. A few years ago, scientists in Península Valdés identified an orca calf named “Melanie.” However, as the animal grew, the fin straightened, revealing that it was a male. To correct the initial mistake, they decided to rename him “Mel.” Today, Mel is one of the largest and most successful males in hunting sea lions and elephant seals in the Peninsula.
Both males and females lose the ability to keep their dorsal fin erect when held in captivity in an aquarium. The fin inevitably falls to the side. Many experts believe that this is due to the stress and depression caused by captivity.
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