Flatheads grow to a length of 155 cm (61 in) and may weigh up to 56 kg (123 lb), making it the second-largest North American catfish (after the blue catfish, Ictalurus furcatus). The average length is about 25-46 in (64-117 cm). Their maximum recorded lifespan is 24 years. Males are mature from 16 cm (6. 3 in) and 4 years of age, while females mature from 18 cm (7. 1 in) and 5 years of age, but may mature as late as 10 years. The world angling record flathead catfish was caught May 14, 1998, from Elk City Reservoir, Kansas, and weighed 123 lb 9 oz (56. 0 kg), however a record from 1982 shows that the flathead catfish would be North Americas longest species of catfish, after a specimen pulled from the Arkansas river that measured 175 cm (69 in. ) and weighed 63. 45 kg (139 lbs and 14oz. ).