A Mars study of over 26,000 people across 14 countries found that uncertainty about a pet's medical history and behavioral background, combined with lack of expert guidance, deters people from adopting pets. However, nearly 1 in 3 people said they would like to adopt if given the right support and information.
- 58% of current pet owners did not adopt their pet, but 28% said they would like to adopt with proper guidance and support
- Top adoption concerns include unknown medical history (33%), behavioral background (27%), and household compatibility (25%)
- 71% of adopters changed their pet's diet after leaving the shelter, showing need for expert nutrition guidance
- Mars launched the Adoption Hub offering expert advice and pre- and post-adoption resources to build adopter confidence
- The 2026 Mars Global Adoption Weekend will expand to over 30 countries with the 3-3-3 rule helping new pet owners: 3 days for safety, 3 weeks for routines, 3 months for settling in
Uncertainty about an animal's background and a lack of expert advice can deter people from adopting pets, according to new research from Mars. The company described the study as the largest pet adoption study of its kind.
Mars released the research ahead of the 2026 Mars Global Adoption Weekend. The study builds on the Mars State of the Pet Homelessness Project and examines the barriers people face when considering pet adoption and how those barriers can be overcome to help more pets find and remain in homes.
The survey of more than 26,000 people across 14 countries found that 58% of current pet owners did not adopt their pet. However, nearly 1 in 3 (28%) said they would like to adopt in the future, given the right guidance and support.
Adopters cite unknowns as top concerns
Among respondents considering adoption, the most common concerns involved unknown medical history (33%), behavioral background (27%) and household compatibility (25%).
The study also found that 71% of adopters changed their pet's diet after leaving the shelter. Mars said expert support can help pet owners manage that transition and ensure their pets receive appropriate, complete and balanced nutrition.
"Adopting a pet is an exciting and rewarding experience, but practical guidance is key to building confidence and helping pets and their owners thrive together," said Dr. Esther Bijsmans, a veterinarian and pet nutrition and health science expert at Mars Pet Nutrition.
"When welcoming home a new pet, we encourage pet parents to follow the 3-3-3 rule: the first three days are about helping a new pet feel safe; the first three weeks are about establishing routines, learning the household dynamic and building trust; and by three months, most pets will have begun to settle in. Patience and bond-building play a central role," she explained.
"Nutrition also plays a vital role in a pet's overall well-being," continued Bijsmans. "A common mistake is switching food too quickly. Instead, gradually transition to a new diet over seven to 10 days to support healthy digestion and help pets adjust comfortably."
Mars launches Adoption Hub
Mars is launching the online Mars Adoption Hub, which offers advice from experts, including the Waltham Petcare Science Institute, along with resources for pre- and post-adoption support.
Respondents who had adopted said the most fulfilling milestones were seeing an adopted pet become relaxed and comfortable at home (43%) and seeing the pet become part of the family (41%).
"Bringing a pet home should be an exciting milestone, not an overwhelming one," said Anthony Guerrieri, vice president of corporate affairs, pet nutrition, at Mars. "What this research clearly shows is that people have the heart to adopt, but they often second-guess whether they have the know-how. By giving people clear, trusted guidance from day one and supporting shelters through our Mars Global Adoption Weekend, we want to take the guesswork out of adoption and help people feel completely confident bringing home a new pet."
Global Adoption Weekend expands
The 2026 Mars Global Adoption Weekend will expand to more than 30 countries, supporting more local shelters than in previous years.
Prospective adopters can visit the Mars Adoption Hub to find participating shelters during Global Adoption Weekend and access resources to prepare for a new pet.
