A teenager has discovered a jaw of a mastodon – an ancient relative of the elephant and mammoth – on a farm in southern Iowa by a teenager.

The bone still has a row of teeth attached and is the second fossil to have been discovered on the farm in the last 30 years.

It is thought to have belonged to a young member of the prehistoric animal that may have stood up to seven foot tall and lived in ancient Iowa around 34,000 years ago.

The species went extinct around 10,000 years ago, possibly due to changes to their habitat, say scientists.

A teenager has discovered a jaw of a prehistoric mastodon (pictured) – an ancient relative of the elephant in southern Iowa on a farm where another mastodon fossil was found 30 years ago

Humans have long been blamed for hunting the American mastodon to extinction but DNA testing shows they died out long before.

UI’s Palaeontology Repository has a number of prehistoric fossils from Iowa, many of which are large mammals that lived in the last 150, 000 years. The image shows a nearly complete lower jaw bone with worn down teeth of an adult mastodon from the university

The species (pictured) went extinct around 10, 000 years ago, possibly due to changes to their habitat, although scientists remain unsure (stock picture)

‘I think people are finding stuff all the time,’ she said.

‘Maybe they are out canoeing or fishing on a bank. Farmers, in particular, on the land can spot things pretty easily.’

Last year, fossil hunters Michigan unearthed the bones of a mastodon which they claim is the most complete skeleton recovered in the region since the 1940s. The remains are one of the most complete specimens uncovered in decades (pictured)

The bone has the teeth of the mammal still attached and is the second fossil to have been found on the same farm (show in map) in the last 30 years

The findings indicated that mastodons suffered local extinction several tens of millennia before either human colonisation – the earliest estimate of which is between 13,000 and 14,000 years ago.