Injured giraffes are at higher risk of dying

Abstract

Animals in the wild can suffer from diseases that can then affect their ability to move. Wildlife is also directly impacted by humans hunting animals for food. In particular, scientists have reported that skin diseases and injuries caused by wire snares, set by people to trap animals in the wild for bush meat, can affect giraffes and their ability to move normally. Most previous research has only been done on captive animals in zoos and with giraffes that suffer from a skin disease that affects their mobility. Recently, an international collaboration between researchers based at universities and zoos in the USA and Namibia recorded videos of giraffes in the wild in Uganda with skin diseases and/or wounds from wire snares.But first, Laura Bernstein-Kurtycz and colleagues collected video of four Masai giraffes (Giraffa tippelskirchi) walking at the Cleveland Metroparks Zoo and used it to quantify the movements of healthy giraffes by measuring how long their stride was, the footfall timing between the back limb and the front limb, how fast the animals were walking, and low long each foot remained in contact with the ground. Additionally, they measured the giraffe's neck movements, up and down as well as back and forth during each stride. After completing their pilot study at the zoo, Michael Brown (Smithsonian National Zoo and Conservation Biology Institute, USA) and J. Evenhuis (Case Western Reserve University, USA) filmed 52 male Nubian giraffes (G. camelopardalis camelopardalis) in the Murchison Falls National Park, Uganda, for more than a year. Bernstein-Kurtycz and colleagues then classified the 52 giraffes into a healthy group, a group with skin disease, a group with wounds from wire snares and a group that had both skin disease and wounds from snares, and analysed their walking movements from the movies.They discovered that skin disease found on the Nubian giraffes did not affect their walking. This might be partially because the disease was found only around the neck region. In contrast, the giraffes that had wounds caused by wire traps had a shorter stride length and slower walking speeds, the limb that was wounded spent less time in contact with the ground bearing weight, and they tended to keep both limbs on the same side of the body in contact with the ground almost simultaneously, possibly to spare the wounded limb from bearing too much weight. In contrast, there were no meaningful differences in the neck movements between the healthy group and any of the groups that had incurred wounds from snares and those that had the skin disease.Traps set by humans have a damaging effect on animals, even if they are not the intended targets. Bernstein-Kurtycz and colleagues have demonstrated that the injuries to these majestic animals caused by wire traps force the giraffes to walk more slowly and unevenly, leaving them vulnerable to attack and predation by lions. Such injuries can also affect their ability to migrate efficiently, locate and compete for mates, and dominant males that are wounded may be unable to protect their mates from males competing to mate with them. Describing how a colleague reported that 257 live giraffes were freed from wire snares in the Murchison Falls National Park between February 2019 and December 2021, the team state that the risk posed by human activity to this endangered population is clearly significant, and conclude that ‘identifying and quantifying potential threats to this population is of global consequence for their conservation’.