Emerging Physiological Approaches for Population Management in Stray and Wild Animals

The increasing population of stray and wild animals in India has emerged as a significant challenge, impacting public health, biodiversity, and animal welfare. India is home to the largest stray dog population globally, with numbers doubling from 35 million in 2020 to 60–65 million by 2023, alongside increasing stray cat and wildlife populations. This overabundance contributes to road accidents, crop and livestock losses, zoonotic disease transmission, and escalating human–animal conflicts. Due to these growing issues, it is essential to control the population of these animals effectively and humanely. Traditional population control methods such as culling and poisoning are often ineffective, ethically contentious, and unsustainable. Fertility control presents a humane and long-term alternative, with promising approaches including surgical sterilisation, immunocontraception, hormonal regulation, gene silencing, chemical sterilants, and targeted cytotoxin delivery. Non-surgical methods, such as vaccines against GnRH, zona pellucida, or sperm antigens, as well as innovative gene-silencing techniques using siRNA delivered via hypothalamus-targeting viral vectors and herbal contraceptives, have shown efficacy in suppressing reproductive functions. Emerging technologies like AMH transgene therapy, rotational immunocontraception, and targeted contraceptive vaccines offer species-specific, reversible, and minimally invasive solutions. While challenges remain in cost, logistics, and long-term efficacy, advancing fertility control strategies tailored to species and ecological contexts holds great potential for reducing human–animal conflicts, mitigating zoonotic risks, and preserving ecological balance humanely and sustainably.