Harbin, April 18 (Xinhua) -- A wild Siberian tiger family consisting of four members has been spotted in northeast China's Heilongjiang Province.

The tigers, which include one mother and three cubs, were caught by an infrared camera in Heilongjiang's Suiyang early this year, the management bureau of Northeast China Tiger and Leopard National Park said Thursday.

A Siberian tiger normally gives birth to two to four cubs at a time, and the survival of three is really rare considering the natural environment in the wild, said Zhou Shaochun, a researcher at the provincial wildlife institute.

Zhou estimates the cubs are around six months old, adding that they "look very healthy."

China has intensified protection efforts for Siberian tigers in recent years, which led to rising numbers of the big cat.

The country's Northeast China Tiger and Leopard National Park was built in 2017 as a sanctuary for highly-endangered Siberian tigers and Amur leopards.

This is the first time that a big cat family has been caught on camera in Heilongjiang since 2017, Zhou said.

Siberian tigers, otherwise known as Amur or Manchurian tigers, mainly live in eastern Russia, northeast China and northern part of the Korean Peninsula.