What kind of animal is a finless porpoise? We will explain its characteristics, ecology, and habitat (fish that can be seen in the Seto Inland Sea region and aquariums). Finless porpoises are very small and cute dolphins. They live widely in the Indian Ocean, from the Persian Gulf to Pakistan, India, and Bangladesh.
What is a finless porpoise? About basic status
The finless porpoise is a small dolphin that belongs to the porpoise family, genus Porpoise. The scientific name is Neophocaena phocaenoides, and the kanji is Sunname. The total length is 1.5-2m and the weight is 50-60kg. The list of information is as follows.
| Japanese（和名） | スナメリ |
| English（英名） | Finless porpoise |
| scientific name(学名) | Neophocaena phocaenoides |
| classification（分類） | Mammalia、Cetacea、 Hylobatidae、Symphalangus 哺乳綱、クジラ目、ネズミイルカ科、スナメリ属 |
| IUCN Status(保全状況) | ENDANGERED |
| Length（体長） | 1.5-2m |
| Weight（体重） | 50-60kg |
scientific classification
- 界：動物界 (Animalia)
- 門：脊索動物門 (Chordata)
- 綱：哺乳綱 (Mammalia)
- 目：クジラ目 (Cetacea)
- 亜目：ハクジラ亜目 (Odontoceti) – 歯のあるクジラ類
- 科：ネズミイルカ科 (Phocoenidae)
- 属：スナメリ属 (Neophocaena)
- 種：Neophocaena phocaenoides（スナメリ）
About habitat
Finless porpoises are mainly distributed in ocean areas such as the Indian Ocean. Currently, they can be seen in places such as Ise Bay, Sendai Bay, and the Seto Inland Sea in Japan. You can see photos of the heads, backs, and bumps of creatures on the internet. There is a lot of material available and research is progressing.
- Geographic Distribution
Distribution Area: Western Indian Ocean to Southeast Asia and East Asia coasts
Coastal China, Yellow Sea, East China Sea, Gulf of Vietnam, Gulf of Thailand, etc.
In Japan, they have been spotted in coastal areas such as the Seto Inland Sea and Tokyo Bay.
- Water Characteristics
Prefers shallow coastal areas
Shallow waters and bays with depths of 10-50m
Also found in estuaries and inland bays
Can adapt to low-salinity brackish waters
- Movement and Schooling
Travels in small schools (a few to a dozen individuals)
Migrates along the coast in search of food, but rarely ventures into the open sea
- Environmental Conditions
Water Temperature: Prefers warm coastal areas
Shallow waters with abundant food are key to survival
Habitat is affected by overfishing and development
feature is? What kind of creature is it?
The finless porpoise has a silvery-white body color and a rounded head. The tail fin is crescent-shaped. Finless porpoises have no dorsal fin, making them very distinctive and conspicuous. They are rarely seen in the open ocean, so humans rarely see them. Finless porpoises usually live in shallow waters up to 50 meters deep and can be seen at river mouths.
- Physical Characteristics
Body Type: Small, rounded toothed whale
Body Length: Approximately 1.4-2.0 m in adults
Weight: 50-70 kg
Dorsal Fin: Small, triangular, and inconspicuous
Face: Rounded snout, lacking a long beak like a dolphin’s
Color: Gray back, whitish underside, and generally solid, smooth body
- Movement/Behavior
Swim in shallow coastal waters, moving in small groups (a few to a dozen individuals)
Rarely exhibiting sharp jumps or flashy movements, they tend to swim calmly
Move slowly while searching for food
- Diet
Carnivorous (mainly fish-eating)
Preys on small fish, shrimp, squid, etc.
Preys in shallow waters, moving quickly near the seabed or underwater
- Sociality
Live in small groups
Communicate calmly within the group
Shy of humans, tending to avoid boats and noise
What is your personality like?
Finless porpoises are highly social animals that value discipline. They are usually seen in groups. They often act alone.
- Gentle and Timid
Generally docile and calm in nature
Sensitive to sounds and activity from humans and boats, and will immediately flee when approached
Rarely exhibits flashy jumps or aggressive behavior
- Sociality
Live in small groups (a few to a dozen individuals)
Swim and forage cooperatively within the group
Rarely engage in territorial disputes or fierce competition, coexisting peacefully
- Highly Cautious
Swim slowly near the surface, but will quickly dive if they sense danger
As a coastal fish, they are sensitive to environmental changes and human presence
- Feeding and Behavioral Characteristics
Feeding is calm and planned
Cooperative group behavior is observed to efficiently catch small fish and shrimp
What does the ecology look like?
Finless porpoises live on fish, crustaceans, and invertebrates. The breeding season is uneven and the gestation period is about 10 months. In the wild, they can live up to 23 years.
- Habitat
Living in coastal areas, estuaries, and bays
Mainly active in shallow waters 10-50m deep
Can live in brackish waters of bays and estuaries
Rarely ventures into the open ocean
Prefers shallow waters and coastal areas with abundant feeding grounds
- Diet
Carnivorous (mainly fish-eating)
Preys on small fish, shrimp, squid, etc.
Catches prey by swimming quickly through the water
Forages while moving along food-rich coastal areas
- Sociality/School Structure
Live in small schools (several to a dozen individuals)
Swim cooperatively within the school to search for feeding grounds
Rarely engages in social conflict, coexisting peacefully
- Behavior
Diurnal, active during the day
Swim slowly near the surface, searching for food
Swim quickly to avoid danger
Disperse and search for food while moving in schools
- Reproduction
Sexual maturity: 2-4 years
Gestation period: Approximately 10-11 months
Litter size: Usually one pup
Rearing: Carried by the mother and nursing for several months
Pups are dependent on their mother for survival and follow their parents on the surface and in shallow waters.
Are there any natural enemies?
Sharks are the biggest threat to finless porpoises.
About Finless Porpoise Baby
This article explains the baby finless porpoise (Neophocaena phocaenoides). As a small, coastal toothed whale, it is highly dependent on its mother.
- Birth and Physical Characteristics
Birth Weight: Approximately 5-10 kg
Body Length: Approximately 70-90 cm
Appearance: Approximately the same body shape as an adult, but smaller and with softer skin
Dorsal Fin: A small, prominent triangular dorsal fin develops as the baby grows
Snout: Short and rounded, without a dolphin-like beak
- Dependence on Mother
Swim alongside their mother for the first few months of life
Nursing period: Approximately 6-12 months
They cling to their mother’s back or nearby, and are protected by their mother in times of danger
- Growth and Development
Acquiring the Ability to Swim Unassisted: Begins to swim alongside their mother within a few weeks of birth
Acquiring Foraging: Learns by watching small fish caught by their mother
Social Learning: Learns by observing school movements and danger avoidance
- Behavioral Characteristics
Develops motor skills while playing alongside their mother
Learns to dive and change direction underwater
Sensitive to danger and stimuli, and is dependent on their mother’s instructions and movements
- Protection from predators
Because they cannot defend themselves against predators on their own, the protection of their mother and herd is essential.
Early learning diving skills increases survival rates.
Are finless porpoises an endangered species?
The finless porpoise is listed as an endangered species. This species is particularly endangered in China’s Yangtze River basin, where it is endangered. Since it can only be seen in clean oceans, marine pollution by humans is the biggest threat, and we are in a critical situation due to the destruction of the environment by humans.
- IUCN Assessment
Classification: Vulnerable (VU)
Reason for Assessment:
Limited to coastal areas, its distribution is limited.
Significant impacts from human activities.
- Threat of Extinction
Conflict with Fisheries
Frequent deaths occur as bycatch (entanglement) in bottom trawls and set nets.
Hits are particularly severe in areas with heavy coastal fishing.
Habitat Degradation
Habitat decline due to reclamation at estuaries and coastal areas, industrial development, and pollution.
Water pollution and noise are also sources of stress.
Decreased prey.
A decline in coastal prey such as small fish and shrimp affects survival.
- Conservation Status
Habitat protection is being promoted under coastal protected areas and international regulations.
International trade is restricted by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).
Preventing bycatch from fishing and development is important.
Can finless porpoises be kept as pets?
Finless porpoises are an endangered species and cannot be kept by the general public. We recommend viewing them at an aquarium and having them show you around at events.
- Difficulty in Breeding
① Unique Habitat
Marine mammals that live in shallow coastal and estuary waters
Requires specific environmental conditions, such as water depth, current, and salinity.
Cannot be reproduced in a home aquarium or small pool.
② Sociality and Stress
They are social creatures that live in small groups, making solitary breeding unsuitable.
Highly intelligent, they can become stressed and aggressive in a cramped environment, leading to health problems and aggression.
③ Difficult to manage their diet
They prey on small fish, shrimp, squid, etc.
It is impossible to properly manage the freshness and variety of seawater and food at home.
④ Difficult to manage health
Lack of seawater environment, disease prevention, and exercise space can damage their health.
Wild individuals are highly susceptible to stress.
- Legal Restrictions
Finally, finless porpoises are subject to wildlife protection laws and the CITES Convention in many countries.
Capturing, importing, and breeding are illegal and subject to penalties.
In Japan, breeding is prohibited without special permission.
- Safety Issues
Wild finless porpoises are not accustomed to humans and are at high risk of stress and aggression.
They are also at risk of diseases and parasites specific to marine mammals.
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