Microplastics in wild tapir and anteater blood rise with human land use

Microplastics were present in 43 of 47 wild lowland tapirs and giant anteaters sampled in Brazil, and blood concentrations were higher in animals whose ranges included more human disturbance. The study, published in Nature and led by Dr Marcia de Almeida Monteiro Melo Ferraz of the University of British Columbia (Kelowna), is described as the first to link landscape-level human activity to microplastic burdens in individual free-living terrestrial mammals.

Closing a gap in exposure data

Microplastics, defined as plastic fragments smaller than 5 mm, travel through the air and in rain, rivers, groundwater and floods. They have been detected in terrestrial wildlife before, and experiments show harm to many species. What had been missing was a quantitative connection between where an animal lives and how much plastic it carries.

Justin Calabrese, a team leader at the Center for Advanced Systems Understanding (CASUS) at Helmholtz-Zentrum Dresden-Rossendorf, a co-author, said that establishing the link required three kinds of data at once: microplastic measurements from living wild animals, fine-scale movement records and high-resolution maps of landscape disturbance. Datasets combining all three did not previously exist.

Tracking animals and sampling blood

The team studied 26 lowland tapirs (Tapirus terrestris) and 21 giant anteaters (Myrmecophaga tridactyla) across the Amazon, Cerrado and Pantanal regions. Blood samples were analysed for microplastics, while GPS tracking showed where each animal travelled and how close it came to human activity and infrastructure.

Movement data were processed with ctmm (continuous-time movement modelling), an open-source software package developed by Calabrese's group over about 15 years. It reconstructs likely paths between recorded GPS fixes and estimates home ranges, indicating how much time an animal spends in different areas.

What the samples showed

Particles were found in 43 of the 47 animals. Blood concentrations were significantly higher in free-ranging animals whose home ranges contained more intensive human disturbance, and also in those living nearer to waste management facilities.

Animals in the Pantanal, a remote wetland, were an informative contrast. Microplastics were found in every animal sampled there, including some living more than 65 km (40 miles) from human infrastructure. Concentrations were substantially lower, and GPS data indicated no direct exposure to human-modified landscapes. This suggests that atmospheric and other transport spreads plastic particles widely, even into areas that appear pristine.

Implications for research and management

The authors argue that better waste management around settlements could markedly reduce microplastic levels in wildlife. They highlight rapidly developing countries such as Brazil, where waste infrastructure has lagged behind the expansion of settlements into frontier areas. Suggested local measures include buffer zones around nature reserves and removing the main nearby sources of plastic pollution.

The work also offers a template for exposure studies, showing how movement ecology, field sampling and laboratory analysis can be combined to tie contamination to specific landscapes. The source material reports associations between exposure and burden in two species; it does not describe health outcomes in the sampled animals, and the sample of 47 individuals is modest. Questions that remain include how the particles reach the blood, which sources and polymer types dominate, and whether the burdens seen here affect wildlife health. Extending the approach to other species and regions would test how general the pattern is.

Source: Microplastics found in wild mammals' blood more than 40 miles from human infrastructure (Phys.org, 12 November 2026).

Image: AI-generated illustration.