A pod of heroic dolphins have been captured on video defending a humpback whale and her calf from a group of five male whales.

The mother named Spirit, and her male calf Sunny, found themselves in danger while swimming off Flinders Bay on Western Australia’s southwest coast on Sunday, when the group of males humpbacks began competing to mate with the mother.

Success for one of the males could have separated Sunny from Spirit, leading to the calf’s death.

Members of Whale Watch WA, who filmed the event, watched on in amazement as 10 to 15 bottlenose dolphins suddenly came to the aid of the female humpback and her son, who the male whales chased for more than 30 minutes.

The mother, named Spirit, and her male calf, Sunny, found themselves in danger while swimming off Flinders Bay, in Augusta, on Sunday (pictured)

The dolphins gathered around the tired female humpback.

One of the dolphins even flashed its teeth toward the male humpbacks in a sign of aggression.

Spirit was forced to swim close to the Whale Watch WA vessel in an effort to shelter her young calf as the dolphins came to her defense.

‘Truly remarkable’: Bottlenose dolphins surrounded the humpbacks to protect them from the males

The mother protected her young calf by all means necessary in the face of danger

The female humpback kept her calf sheltered close to the vessel of Whale Watcher WA

One of the male humpbacks then began to act as an ‘escort’ for the mother and her calf and chased the smaller males away.

Whale Watch WA have hailed the experience as evidence of the lengths a mother humpback will go to in order to protect her offspring.

They have referred to the co-operation between the whales and dolphins as ‘truly remarkable’ and a ‘true once in a lifetime experience’.