Cattle once served as working animals for farmers in Hong Kong, but changing economic conditions eventually led to the decline of cattle farming. Then, in the 1970s, some cattle were abandoned and began roaming freely. Generations later, the animals have become a distinctive feral population, living with little of the human management that shaped domestic cattle.
The results revealed a population that retained surprisingly high genetic diversity despite its small size, while also carrying genetic signatures linked to its long history of isolation, ancient wild-bovine ancestry and adaptation to the local environment. However, the results of the research do not mean that all genetic differences have been confirmed as adaptations. Now, their DNA is offering clues to what happened after that change. The cattle’s physical appearance is another clue. The feral cattle in Hong Kong come in displaying varied fur patterns, distinct horn shapes, asymmetrical humps, and irregular body profiles . The research team found copy-number variation in genes such as NINL, DEXI, and CIITA that may help explain differences in coat color. The researchers listed a few of these gene regions as candidates whose effects still need to be tested.
A 2026 genome study sequenced 30 Hong Kong feral cattle and compared them with 116 cattle from four major populations.
Genome-wide analysis revealed that Hong Kong cattle were most closely related to East Asian indicine cattle, although the population has developed a genetic signature unique to itself. That makes the population unusually valuable for studying what happens when domesticated animals become feral. Scientists also found that the cattle’s ancestors received some genetic input from banteng and gaur before diverging from other East Asian indicine cattle. The investigators then looked for evidence of natural selection by testing whether certain genome regions were favored during adaptation to the cattle’s environment. Some genomic regions showed associations with traits relevant to survival, such as heat resistance, bone density, and coat pigmentation. A specific genomic region for the ADRA1A gene showed an association with heat stress response. Other genomic regions showed associations with biological functions related to development, immunity, and metabolism. The herd offers a rare example of how domesticated animals evolve when human influence fades. For scientists, the herd is much more than an interesting subject of genetic research. The herd’s wild-bovine ancestry, high genetic diversity, and apparent adaptation could help scientists study how heat, disease, and other pressures shape cattle evolution. For Hong Kong, the wandering herd is a living reminder of the territory’s agricultural history.
A 2020 study had already found that Hong Kong cattle were genetically distinctive and showed evidence of ancestry connected with wild bovines. That earlier work examined 21 Hong Kong cattle alongside 703 animals representing 36 cattle populations and wild species including gaur and banteng. The team sequenced the genomes of the 30 animals at 30x coverage depth. In 2026, the DNA results tell a broader story about how generations of ancestry, isolation, and natural selection shaped the population.
Because it examined each animal’s full genome rather than focusing mainly on selected genetic markers, in the new research, the analysis was more extensive.
