Brown trout are vertebrates that are highly diverse from a genetic perspective, according to The Wild Trout Trust. British brown trout showcase more genetic diversity than any populations in the whole human race. While genetically distinct trout can spawn together and reproduce healthy offspring, many have preserved their unique traits for thousands of years. The species has between 38 and 42 pairs of chromosomes, while humans boast only 23 pairs.
According to the BBC, brown trout survive on a diet of invertebrates as they start life although some of them take to a fish diet later. The larger predatory types are sometimes referred to as ferox trout, which were once believed to be a different species. Sea trout share traits that are similar to those of the brown trout although sea trout are migratory, spending a substantial chunk of their life at sea and occasionally going back to rivers to spawn.
Brown trout have a tendency to grow bigger and have a longer life span than brook trout or rainbow trout, Maryland Fish Facts explains. The species also has a higher tolerance for a wider array of habitat types. Most fishermen believe brown trout are the cleverest of all trout species and are hardest to catch.