While the males return annually, the females return only every other year, often with fresh, deep bites around their heads. The seasonal shark population at the Farallones is unclear, with estimates from thirty to one hundred. The Farallones are unique in the size of the great whites that are attracted. The average length of a full-grown great white shark is , with a weight of , females generally being larger than males. Farallon great whites range between the "smaller" males at to the females, which generally range between . The largest accurately measured great white shark was a female caught in August 1988 at Prince Edward Island off the North Atlantic coast and measured . A killer whale was recorded killing a great white near the Farallones in 1997. Over the decades of study, many of the individual white sharks visiting the Farallones have been nicknamed, often based on their scars and appearances, such as Gouge, The Hunchback, The Jester, and Stumpy. Stumpy, an 18-foot female great white, in particular was well known for her appearance in the BBC documentary "Great White Shark" narrated by David Attenborough and stock footage of her attacks on decoys is often utilized in more recent documentaries, and another example, Tom Johnson, a 16-foot male white shark that was featured in an episode of the 2012 season of Shark Week called "Great White Highway" is believed to be the oldest living white shark so far documented returning to the Farallones, estimated at around 25–30 years old.