This is the dramatic moment two proud stallions faced off in a bloody fight for dominance and mating rights in a herd of wild horses.
The Koniks, or Polish primitive horses, reared up on their hind legs with their teeth bared during the ferocious attack.
Photographer Henri Ton, 41, captured the fight over females at a nature reserve in Loevenstein, The Netherlands.
One stallion could be seen chasing a mare while others fought among themselves.
Mr Ton, who works as an electronic engineer, spends several hours a week observing the herd of 36 horses to better understand their behaviour.
He said: 'The Koniks were put in a nature reserve and left to fend for themselves.
'The public are told to keep their distance and not to feed them so they can remain wild.
'I go looking for them about once a week and have done for over a year now.
'I try to avoid attracting their attention so their behaviour in my pictures is as natural as possible.'
He said the herd is formed from a mix of bachelor groups - young stallions who have been abandoned or rejected and need to play to build up their strength before returning - and harem groups which feature one stallion, around six mares and foals.
There is one lead stallion in the herd, which is the only male allowed to breed.
'Fights with the lead stallion can be very rough and if he is injured the other stallions try to take over.
'Sometimes it is playful, almost like an act or dance, but it can also be very aggressive with bloody injuries.
'The Konik horse is one of the few types of horses able to survive in the wild. They are wild but they have never been aggressive towards me.'