Colder water from the winter months contributed to the deaths of more than 25 dolphins that washed ashore on the Texas coast over the last two weeks, a rescue group said.

Some of the animals were very young with umbilical cords still attached and apparently were either stillborn or separated from other dolphins just after birth, officials said.

At least 17 of the bottlenose dolphins washed ashore along the Galveston County coastline last week, said Heidi Watts, state operations coordinator for the Galveston-based Texas Marine Mammal Stranding Network.

Watts said such strandings are fairly common from January through March, although they tend to peak in February.

Bottlenose dolphins inhabit warm seas throughout the world and generally live 30 to 40 years. The dolphins that washed up on shore probably took ill in reaction to colder water from the winter months, Watts said.