Eurasian Lynx (Lynx lynx)
Anatomy
The Eurasian lynx is a strict carnivore which has a relatively simple gastrointestinal tract due to their very highly digestible diet (Stevens and Hume, 1998; McGrosky et al., 2016). The range of body lengths for the Eurasian lynx is between 80-130cm, while their average weight is found between 15-29kg (Arkive, 2017). For a body weight of 17.5kg, the Eurasian lynx has a total intestine length of 300cm (251cm = small intestine, 48cm = large intestine) (McGrosky et al., 2016). Eurasian lynx are also one of the carnivores known to have a caecum present in their gastrointestinal tract (McGrosky et al., 2016). The digestive tract starts with the mouth, where food is ingested, masticated and swallowed with saliva secretions (DeSesso and Williams, 2008). The bolus of food travels down the esophagus to the unilateral stomach in carnivores (Stevens and Hume, 1998; DeSesso and Williams, 2008). From the stomach (foregut) in carnivores (Stevens and Hume, 1998; DeSesso and Williams, 2008). From the stomach, the ingested material travels through the small intestine (midgut), caecum and large intestine (hindgut) to be excreted out of the anus (DeSesso and Williams, 2008).
Physiology
Obtaining nutrients for an animal to survive, starts with the prehension of food from their environment. The Eurasian lynx use their canine and premolar teeth for prehension by ripping and tearing the carcass (Hume, 2002). Once the food material is in their mouth, physical digestion begins through mastication, and chemical digestion begins through the secretion of saliva and enzymes (DeSesso and Williams, 2008). The material forms a bolus which travels by peristalsis through the esophagus to the stomach (DeSesso and Williams, 2008). The stomach is an acidic environment (pH 1.6-4) which mixes ingested material and secrets hydrochloric acid to help denature proteins (DeSesso and Williams, 2008). From the stomach, the small bolus of chyme passes into the duodenum of the small intestine where secretions from the pancreas, liver and enteric glands mix with the chyme to neutralize the pH (DeSesso and Williams, 2008). The jejunum of the small intestine is where majority of the absorption of nutrients (amino acids and triglycerides) takes place (DeSesso and Williams, 2008). The chyme passes through the ileum to the caecum and large intestine where water is absorbed from the chyme and forms solid feces (DeSesso and Williams, 2008). The solid feces are stored in the rectum until the lynx expels the feces through the anus (DeSesso and Williams, 2008).
Eurasian Otter (Lutra lutra)
Anatomy
The Eurasian otter is a carnivore which has a relatively simple gastrointestinal tract due to their very highly digestible diet (Stevens and Hume, 1998; McGrosky et al., 2016). The range of body lengths for the Eurasian otter is between 57-70cm, while their average weight for adults is found between 7-10.1kg (Arkive, 2017). For a body weight of 4.84kg, the Eurasian otter has a total intestine length of 321cm (McGrosky et al., 2016). McGrosky et al (2016) found in their study that Eurasian otters had an unusually long gastrointestinal tract compared to other terrestrial carnivores. It was hypothesized that the gastrointestinal tract was longer in Eurasian otters due to torso elongation, which increases the basal metabolic rate and the surface:volume ratio (McGrosky et al., 2016). Eurasian otters do not have a caecum present in their gastrointestinal tract (McGrosky et al., 2016). The digestive tract starts with the mouth, where food is ingested, masticated and swallowed with saliva secretions (DeSesso and Williams, 2008). The bolus of food travels down the esophagus to the unilateral stomach (foregut) in carnivores (Stevens and Hume, 1998; DeSesso and Williams, 2008). From the stomach, the ingested material travels through the small intestine (midgut) and large intestine (hindgut) to be excreted out of the anus (DeSesso and Williams, 2008).
Physiology
Obtaining nutrients for an animal to survive, starts with the prehension of food from their environment. Since the main prey of the Eurasian otter is fish, these otters have adapted very strong and sharp tubercles of the molars to quickly catch fish (Knight, 1840). The Eurasian otters also have other adaptions, such as webbed feet and a tiller like tail to control their movement in the water (Arkive, 2017; Knight, 1840). Once the food material is in their mouth, physical digestion begins through mastication, and chemical digestion begins through the secretion of saliva and enzymes (DeSesso and Williams, 2008). The material forms a bolus which travels by peristalsis through the esophagus to the stomach (DeSesso and Williams, 2008). The stomach is an acidic environment (pH 1.6-4) which mixes ingested material and secrets hydrochloric acid to help denature proteins (DeSesso and Williams, 2008). From the stomach, the small bolus of chyme passes into the duodenum of the small intestine where secretions from the pancreas, liver and enteric glands mix with the chyme to neutralize the pH (DeSesso and Williams, 2008). The jejunum of the small intestine is where majority of the absorption of nutrients (amino acids and triglycerides) takes place (DeSesso and Williams, 2008). The chyme passes through the ileum to the caecum and large intestine where water is absorbed from the chyme and forms solid feces (DeSesso and Williams, 2008). The solid feces are stored in the rectum until the otter expels the feces through the anus (DeSesso and Williams, 2008).