World's most complete mammoth was found by a reindeer herder and his sons in Russia in 2007

The large black crate was sent from Russia with Love. Laid on cloth and packed in foam, the world's most complete mammoth arrived in Britain on Monday to go on public display at the Natural History Museum in London.

A reindeer herder, Yuri Khudi, and his sons found the remains in 2007 while searching for wood along the frozen Yuribei river on the Yamal peninsula. The mammoth was sent to Shemanovsky Museum in northern Sibera and named Lyuba, after Khudi's wife. It is the Russian word for love.

Lyuba lived 42,000 years ago and was only 85cm tall and 130cm long – the size of a large dog – when she died at one month old. She was in perfect condition, and scans have revealed how she met her end. Her trunk was filled with mud, leading researchers to suspect that she sank quickly into a mudpool that froze and preserved her body. In the millennia that passed, Lyuba's body became mummified.

"It was thrilling to see her in the flesh," said Adrian Lister, at the Natural History Museum. "The preservation is remarkable. There are parts of her anatomy that we've never seen before."

Scientists have already learned much from Lyuba. Work on her stomach contents found a congealed, brownish-white substance that turned out to be her mother's milk. More mysterious, given that her teeth had not come into use, was the presence of chewed grass. She may have eaten her mother's dung to acquire the gut microbes needed to digest celluose.

Like elephants, mammoths had two fleshy projections at the ends of their trunks. Lyuba's were enlarged and well-suited to grazing on flowers, moss and other low vegetation. There were no trees in her habitat to rip branches from, as elephants do today.

Lyuba is so well preserved that researchers have seen for the first time two flaps of skin that run the whole length of the trunk. "We can only speculate what it was for. It might have been for scooping up snow to get water," Lister told the Guardian.

The Natural History Museum exhibition Mammoths: Ice Age Giants opens on 23 May.