Nile crocodile in Valladolid river? The trail gets 'otter...

Local Police in Simancas, in the province of Valladolid (Castilla y León) received several calls at around noon on Saturday saying they had seen a 1.5-metre (4'11”) crocodile of the type found in the river Nile in Egypt and Sudan, in the confluence of the Pisuerga and Duero rivers.

A police officer also thought he had seen it in the water.

Several areas on the Pesquerela tow-path have been cordoned off as the Guardia Civil's environmental wing, SEPRONA, searches for the croc.

They say if, indeed, it exists, it is likely to have been abandoned by its owner – almost certainly an owner who should not have had it in the first place, since it is one of a long list of exotic creatures which cannot be legally kept by private individuals outside the countries of their natural habitats.

Nile crocodiles are exceptionally dangerous creatures, but they are also nervous and will tend to flee if they see a human, rather than attack.

Egyptians living on the Nile banks, especially Nubian families, keep baby ones as pets – they are small enough to keep in a fish tank – then release them into the river again when they are too big, because adult ones are not compatible with humans in confined spaces.

A biologist identified footprints on the riverbank at the weekend as being 'possibly' those of a crocodile, but said it also 'could be an alligator'.

Experts say a croc would be unable to survive in the low water temperature of the Pisuerga, although the China alligator and the Mississippi alligator are creatures which could cope with the cold river climate 'in semi-hibernation'.

But on Monday, SEPRONA found remains of an otter near the river – and said some of the footprints in the undergrowth were human, not reptile – and, in fact, Madrid's Complutense University biodiversity monitoring group believes the so-called Nile crocodile could in fact be this commonly-spotted water mammal.

Group member Francisco Javier García was quoted in the Portuguese broadsheet Diário de Notícias – given that Portugal 'shares' the Duero river, where it is called the 'Douro' – as saying it would be easy to mistake a swimming otter for a crocodile.

“It's a very simple mistake to make, because crocs travel through the water in a wave-like movement with their eyes and nose above the surface,” García explains.

Even the footprints could be those of an otter, he says.

PR manager at Madrid Zoo, María José Luis, urged the public to 'calm down', saying expert opinion concurred that it was likely SEPRONA was searching for a harmless otter which is native to European rivers in any case.

“It's important to reassure the public about the existence or otherwise of a crocodile in the river until we get to see photographs of it and they can be analysed by experts,” Sra Luis stresses.

“And we must continue to insist that exotic creatures such as crocodiles should never be kept as pets – only in zoological institutions where they can be cared for by experts in their species.”

SEPRONA says it intends to continue the search 'just in case'.

“We don't know whether it's an otter or a crocodile – we're not going to contradict the experts,” says a spokesperson for SEPRONA.

“The search will continue, with its radius increased from five to six kilometres, and whenever we find anything we'll let everyone know.”

In the photo, one of the locals in Simancas is attempting to spot the crocodile in the Pesquerela area of the Pisuerga-Duero confluence.