The Yangtze finless porpoise is one of the most endangered animals in China. Found only in China’s Yangtze River and nearby lakes, such as Poyang Lake and Tian-E-Zhou Oxbow Lake, this unique freshwater porpoise stands out with its small size, rounded head, smooth, finless back, and adorable face. What is even more adorable are their babies.
We aim to shed light on this elusive freshwater marine mammal. We hope to better understand not only how finless porpoises reproduce, but also what they need to continue doing so in a changing and often hostile environment. Each insight is a step toward more effective protection and toward securing a future for this rare and remarkable species.
Mating and Gestation
The species has been in a continuous decline since the early 1980s.
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Yangtze finless porpoises usually mate between May and June, with calves born the following April or May. Finless porpoise gestation is estimated to last 10 to 11 months. Births typically take place in calm, shallow waters. The birthing process itself takes place entirely underwater and can last several hours, depending on the individual porpoise and environmental conditions. During this time, the expectant mother may become more reclusive and seek out quiet areas.
Birth and First Hours of Life
The mother is generally the primary caregiver and remains with her calf until it is fully mature.
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At birth, a finless porpoise calf is highly dependent on its mother for both survival and guidance. In a groundbreaking and closely observed case, the world’s first recorded birth of a Yangtze finless porpoise in a net-cage sanctuary, the newborn calf appeared disoriented and initially struggled to swim or reach the surface to breathe. The mother demonstrated instinctive and attentive care, gently nudging her calf upward to help it take its first breath. Within an hour, it began to move with growing coordination, closely shadowing its mother’s movements. Newborns must rely entirely on their mothers for buoyancy, breathing assistance, and early guidance in navigating their watery world. The early bond between mother and calf is critical, not only for physical survival but for the calf’s social and behavioral development. This crucial early period reveals not only the calf’s rapid developmental progress but also the depth of maternal instinct and the critical importance of maternal care. The strong, immediate bond between mother and calf plays a vital role in the calf’s ability to adapt, survive, and thrive in its new environment. Babies nurse exclusively for about 5-6 months.
Nursing and Weaning
The finless porpoise matures at the age of 4-6 years and is a seasonal breeder.
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The finless porpoise matures at the age of 4-6 years and is a seasonal breeder.
©Huangdan2060 / CC BY 3.0 – Original / License
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The finless porpoise matures at the age of 4-6 years and is a seasonal breeder.
©Huangdan2060 / CC BY 3.0 – Original / License
For the first six months, the calf stays close to its mother, nursing and relying on her for nourishment, protection, and guidance. The mother’s milk provides all the nutrients the calf needs during this time. Around five to six months, calves begin to explore solid foods, such as small fish, gradually transitioning from milk to an independent diet.
By around one year of age, calves are fully weaned, though they may remain close to their mothers. At the time of weaning, young porpoises typically measure about 40 inches in length. This gradual shift toward independence reflects their increasing ability to navigate the river environment and forage independently.
Baby Sizes
Yangtze finless porpoises are not the largest in the Phocoenidae porpoise family.
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Newborn finless porpoises are relatively small, a little over 2 ft. The adult Yangtze finless porpoises aren’t especially huge; they usually grow to 5–6 feet in length, with some rare individuals reaching up to 7 feet 5 inches. The maximum recorded weight is about 159 pounds, although most adults weigh between 65 and 100 pounds. Their compact size makes them agile swimmers, well-suited for navigating the complex waterways of the Yangtze River. Despite their small stature, they are highly intelligent and social animals.
The Finless Porpoise is a Species in Crisis
The Yangtze River is home to the finless porpoise, which is considered critically endangered.
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The early months of a calf’s life are not only biologically demanding, they are also perilous due to the broader threats facing the species.
The List of Threats Facing Finless Porpoises
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Pollution from industrial and agricultural sources
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Habitat loss due to dam construction and development
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Shipping traffic and noise pollution, which can disrupt communication and echolocation
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Fishing gear entanglement
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Food scarcity caused by overfishing
Once numbering in the thousands, the Yangtze finless porpoise population has declined to an estimated 1,000 to 1,800 individuals, resulting in its Critically Endangered status on the IUCN Red List. In such a small and vulnerable population, every successful birth is vitally important, not just for individual survival, but for the long-term viability of the species. Protecting breeding females and ensuring safe conditions for calves to be born and raised is essential to prevent further decline.
Conclusion
Porpoises play an important role in keeping their environment healthy.
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Conservation programs in China, including semi-natural reserves such as Tian-E-Zhou Oxbow Lake, continue to play a significant role in protecting finless porpoises, with recent reports of successful releases and ongoing support for population recovery. Scientists continue to study reproductive patterns, maternal behavior, and calf development to better support population recovery efforts.
The Yangtze finless porpoise is related to the now-extinct Yangtze River Baiji dolphin. The finless porpoise’s survival will depend not only on the strength of its mothers and calves but on the actions taken by humans to protect their waters, food sources, and future.
With continued research, stronger environmental protections, and public awareness, there is still hope that this remarkable species can thrive once again in the waters of the Yangtze. The choices made today will shape whether future generations ever get the chance to witness these intelligent and gentle river dwellers with their beautiful smiles in the wild.
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