Ciliates (Ciliophora) are unicellular organisms, most of which can live freely in aquatic environments. Mobilid ciliates, however, have tied their life histories closely to animal hosts. They commonly inhabit the body surface or gills of aquatic animals, including fishes, mollusks, annelids, and crustaceans, attaching themselves to host tissues by means of an adhesive disc on the aboral side. At the center of the adhesive disc is a ring of specialized denticles that helps anc

Sloths spend much of their day in trees, often moving with their bodies suspended beneath branches while alternately hooking their limbs onto supports ahead of them. In most quadrupedal animals, the limbs primarily bear the forces generated as body weight presses downward against the ground. Sloths frequently experience a very different mechanical situation: their limbs must support the body's weight while it hangs below the point of attachment for prolonged periods. What fea

Nestlings confined to a nest, unable to fly or make a rapid escape, have very few options when a predator enters. Eurasian roller (Coracias garrulus) nestlings, however, have developed an unusual response. When strongly disturbed, they regurgitate an odorous orange liquid from their mouths. Ornithologists had observed this behavior before, but it remained unclear whether the vomit was simply a physiological response to distress or served a specific function. Eurasian roller (

For patients with respiratory failure, maintaining adequate oxygen levels in the blood is one of the most urgent priorities in life-saving care. Mechanical ventilation can be used to support pulmonary gas exchange, while patients with extremely severe respiratory failure may require extracorporeal membrane oxygenation (ECMO). Yet some animals have evolved an unusual survival strategy: when oxygen becomes scarce, they can absorb oxygen through their intestines. This led a Japa

Recent reports have once again raised concerns about food contaminated with Cyclospora cayetanensis in the United States. Looking beyond the latest incident, however, it becomes clear that this parasite has repeatedly entered the U.S. fresh produce supply chain. In 2019, the United States reported 2,408 cases of cyclosporiasis, with some outbreaks linked to imported basil. Another 1,241 cases were reported in 2020, including a large cluster associated with bagged salad mixes

Beginning in 2012, large numbers of brown bullheads (Ameiurus nebulosus) with dark skin lesions were observed in Lake Memphremagog, which straddles the border between Vermont in the United States and Quebec in Canada. Some lesions appeared as flat, darkly pigmented patches, while others developed into conspicuous raised masses, including lesions around the eyes, opercula and mouth. Histopathological examination confirmed that the raised lesions were malignant melanomas. Among

Human upright walking depends on the coordinated action of the legs, spine and pelvis, with the pelvis playing a central role in maintaining balance during every step. Compared with other primates, including chimpanzees (Pan troglodytes), the human pelvis is bowl-shaped. Its upper component, the ilium, is short and broad and curves around the sides of the body. This configuration stabilizes the trunk during single-leg stance, supports the internal organs and provides sufficie

Reptiles have long been shown to exhibit responses such as anxiety, stress, and preference when handled, exposed to novel environments, or choosing preferred foods. However, compared with mammals and birds, research on reptile emotions remains limited. As a result, whether reptiles possess emotional capacities similar to those of other vertebrates remains an important question in animal behaviour research. Researchers often use cognitive judgement bias tests to assess animals

Vomiting is unpleasant, but it serves as an important protective mechanism. When toxic substances, gastrointestinal irritation, or certain drugs threaten the body, the nervous system coordinates the esophagus, stomach, diaphragm, abdominal muscles, and respiratory muscles to expel gastric contents through the mouth. Cats, dogs, ferrets, primates, and shrews are all capable of vomiting. Laboratory mice, however, have rarely, if ever, been observed to vomit. It was therefore un

Reptiles have become increasingly popular pets around the world. Many people believe that reptiles rely primarily on instinct rather than possessing the rich emotional lives often associated with cats and dogs. As a result, they are often assumed to require little space and only simple enclosures. However, growing research suggests that these assumptions may underestimate the abilities of reptiles. Sentience is generally understood as the capacity to experience both positive