Reports of wild boar and wild boar invasions triple in Brazil in the last ten years

The national wild boar control plan (Sus scrofa L.) won at the turn of the year, and Ibama (Brazilian Institute for the Environment and Renewable Natural Resources) has not yet announced what measures will be taken.

Data on the occurrence of wild boar and wild boar (crossing with domestic pigs) across the country has not been updated in Simaf (Fauna Management Information System) since August 2021, when the last newsletter was published. While official numbers are lacking, however, there are reports of wild pig sightings, native to Asia, Europe and North Africa, and damage to crops.

A recent survey by a group of Brazilian and foreign researchers pointed out that the presence of the animal has tripled in the last ten years, reaching states free of invasion until then, such as Pará and Pernambuco. According to the study, 1,152 municipalities reported sightings in 2022, with emphasis on the South and Southeast regions. In 2012, ten years ago, there were 370 municipalities.

In the country, the accelerated dissemination of the species has taken place since the beginning of the 1990s. Biologist Carlos Salvador, one of the researchers responsible for the survey, recalls that, although sport hunting is prohibited in Brazil, there is an exception for the slaughter of wild boar, authorized by Ibama since 2013 to control the species.

In his view, however, ironically, this has contributed to the spread of the wild boar, due to the interest of places that explore sport hunting. Transporting the live animal between different states with the intention of keeping populations around for recreational hunting exacerbates the problem, he reckons.

“Today things are very mixed up. It has become difficult to differentiate hunting for slaughter from sport. There are people who link the request for control authorization to the practice of sport. In the interpretation of this group, the government has generally released it”, he says.

With the prescription of the national plan, on December 31, although the slaughter is still authorized by Ibama, the country is in a limbo in terms of control practices. The instrument organized more than 70 actions, with deadlines for execution and defined costs, distributing tasks among representatives of federal and state public agencies, universities, civil society and the rural sector. Without the document, therefore, the issue is disorganized in the country.

Considered one of the 100 worst invasive species in the world, the wild boar also benefits from the low number of predators in nature.

“More large native carnivores, such as jaguars, would help a lot”, explains Salvador, who acted as a consultant for the federal management plan.

Strong and resilient, the flocks roam freely through agricultural mosaics in search of grains, roots, vegetables and tubers, damaging crops. Corn is one of the favorite foods.

In the village of Criúva, in the Serra Gaúcha, farmers who act as controllers in their free time lost corn plantations —and even calves— in the attacks.

“The wild boar is the new king of the jungle and we no longer see light at the end of the tunnel. In addition, controllers are hunting less due to lack of time and due to the cost of equipment, such as ammunition. We have to pay for everything “, complains Fernando Giordani, a producer who lost two hectares of corn during an invasion of his farm.

In addition to agricultural losses, the wild boar poses a health risk to pig farming, as it can carry pathogens, such as viruses, and transmit them to domestic pigs raised on farms. Swine fever (classical and African), Aujeszky’s disease (pseudorabies), foot-and-mouth disease and brucellosis are some of the pathologies with the potential to decimate herds if there is contact between a contaminated wild species and commercial pigs.

Uncontrolled spread also poses a threat to public health. Contact with blood at slaughter or ingestion of meat from an uninspected animal can transmit zoonoses to humans.

A survey by Embrapa Suínos e Aves obtained exclusively by Sheet detected densities of about 8 individuals per km^two in the border region with Uruguay, in Rio Grande do Sul, and around 5 individuals/km^two in western Santa Catarina. Embrapa has been conducting the Javali Phase 2 health monitoring project since 2019.

For biologist Marcos Tortato, an associate researcher at the Embrapa unit, the numbers are relatively high, especially when compared to the density of white-lipped peccaries and collared peccary, the most common native pigs in the country. Santa Catarina, for example, has only three residual populations of peccary.

“Unfortunately, we cannot say whether they are declining or growing in these regions because we don’t have other estimates”, explains the researcher, noting that the lack of data makes management difficult.

For him, the absence of a contingency plan is another limitation of the country, as well as the loss of biodiversity. As for the controllers, the management plan concentrated responsibility for resolving the problem on the group, which claims support.

“We only have expenses and there are few of us to handle so many wild boars”, stresses zootechnician Leonardo Tedesco, from Veranópolis (RS). Between January and August 2021 alone, the group slaughtered 333,000 individuals across the country.

In addition to Rio Grande do Sul, where the first wild boar dispersals took place, producers in Mato Grosso do Sul also report difficulties. A rancher in the state who preferred not to be identified said he lost 80 hectares of corn for silage last year when herds (flocks) of wild boar attacked the crop.

In Pindamonhangaba (SP), farmer Henrique Pereira harvested 29 carts of corn, when he expected to harvest 33 last year. He calculates the loss of six tons of grain in nocturnal attacks on the crop.

“As if the lack of rain and the high price of inputs were not enough, now comes the pig [o javali]. We can’t plant more”, he complains.

Despite the devastation at the sites, attacks on humans are rare, say scientists. They only occur when the animal is cornered, threatened or someone approaches females with young.