Nick Upton / Toothed / Serrated wrack (Fucus serratus) submerged at mid tide, near Falmouth, Cornwall, UK, August.

Nick Upton / Split level view of Toothed / Serrated wrack (Fucus serratus) clumps at mid tide, near Falmouth, Cornwall, UK, August.

Adrian Davies / Serrated wrack (Fucus serratus) UK, July

Robert Thompson / Serrated wrack {Fucus serratus} exposed at low tide, Ballyhenry Point, Strangford Lough, County Down, Northern Ireland, UK, September

David Tipling / Toothed / Serrated wrack {Fucus serratus} exposed at low tide, Isles of Scilly, Cornwall, UK

Jason Smalley / Serrated wrack {Fucus serratus} and Kelp, probably Tangle oarweed {Laminaria digitata} Stackpole, Pembrokeshire, Wales, UK

Geoff Simpson / Serrated wrack seaweed {Fucus serratus} exposed at low tide, Gwynned, Wales, UK

Niall Benvie / Serrated (Toothed) wrack (Fucus serratus) with marine mollusc (Littorina littoralis) on the seaweed. Scotland, UK, Europe

Kristel Richard / A purebred Lusitano stallion galloping in the arena at the Companhia das Lezírias Stud Farm, Samora Correia, Santarém, Portugal, July 2011

Kristel Richard / A purebred Lusitano colt (with his mane and tail cut to mark his first year) trotting in the arena at the Companhia das Lezírias Stud Farm, Samora Correia, Santarém, Portugal, July 2011

Kristel Richard / A rare Sorraia stallion cantering, Coudelaria Nacional (National Stud Farm), in Alter do Chao, District of Portalegre, Alentejo, Portugal.

Kristel Richard / A purebred Lusitano stallion canters in the arena at the Companhia das Lezírias Stud Farm, Samora Correia, Santarém, Portugal, July 2011

Kristel Richard / A purebred Lusitano stallion cantering in the arena at the Companhia das Lezírias Stud Farm, Samora Correia, Santarém, Portugal, July 2011

Kristel Richard / Band of rare Sorraia mares and foals running, Coudelaria Nacional (National Stud Farm), in Alter do Chao, District of Portalegre, Alentejo, Portugal.

Kristel Richard / A rare Sorraia breeding stallion courting one of his Sorraia mares, Coudelaria Nacional (National Stud Farm), in Alter do Chao, District of Portalegre, Alentejo, Portugal.

Kristel Richard / Rare Sorraia colt and filly playing together, Coudelaria Nacional (National Stud Farm), in Alter do Chao, District of Portalegre, Alentejo, Portugal.

Kristel Richard / Band of rare Sorraia mares and foals running, Coudelaria Nacional (National Stud Farm), in Alter do Chao, District of Portalegre, Alentejo, Portugal.

Kristel Richard / Portrait of a rare Sorraia breeding stallion (right) courting one of his Sorraia mares, Coudelaria Nacional (National Stud Farm), in Alter do Chao, District of Portalegre, Alentejo, Portugal.

Kristel Richard / Portrait of a rare Sorraia breeding stallion, Coudelaria Nacional (National Stud Farm), in Alter do Chao, District of Portalegre, Alentejo, Portugal.

Kristel Richard / A rare Sorraia stallion cantering, Coudelaria Nacional (National Stud Farm), in Alter do Chao, District of Portalegre, Alentejo, Portugal.

Kristel Richard / Two rare Sorraia stallions pulling a cart, at the Coudelaria Nacional (National Stud Farm), in Alter do Chao, District of Portalegre, Alentejo, Portugal.

Kristel Richard / Portrait of a rare Sorraia foal, Coudelaria Nacional (National Stud Farm), in Alter do Chao, District of Portalegre, Alentejo, Portugal.

Kristel Richard / Portrait of a rare Sorraia colt, Coudelaria Nacional (National Stud Farm), in Alter do Chao, District of Portalegre, Alentejo, Portugal.

Kristel Richard / Two rare Sorraia stallions pulling a cart in front of the Coudelaria Nacional (National Stud Farm), in Alter do Chao, District of Portalegre, Alentejo, Portugal.

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) young black stallion postures with foreleg raised to challenge another stud, Pryor Mountain Wild Horse Range, Montana

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) young stud colts, members of bachelor band, graze, play and fight together near Oshoto, northern Wyoming

Yva Momatiuk & John Eastcott / Spanish Mustang (Equus caballus) young bachelor studs interact and graze together, northern Wyoming

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) mare, foal and stud, family band grazing in summer, Montana

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) mare reaches out to her yearling stud colt, caressing him, Montana

Yva Momatiuk & John Eastcott / Mustang (Equus caballus), young stud colts running, members of a bachelor band, Oshoto, northern Wyoming