Monitor lizard in the context of "Live food"

Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the full set of genes of their single parent and thus the newly created individual is genetically and physically similar to the parent or an exact clone of the parent. Asexual reproduction is the primary form of reproduction for single-celled organisms such as archaea and bacteria. Many eukaryotic organisms including plants, animals, and fungi can also reproduce asexually. In vertebrates, the most common form of asexual reproduction is parthenogenesis, which is typically used as an alternative to sexual reproduction in times when reproductive opportunities are limited. Some monitor lizards, including Komodo dragons, can reproduce asexually.

While all prokaryotes reproduce without the formation and fusion of gametes, mechanisms for lateral gene transfer such as conjugation, transformation and transduction can be likened to sexual reproduction in the sense of genetic recombination in meiosis.

Animal cognition encompasses the mental capacities of non-human animals, including insect cognition. The study of animal conditioning and learning used in this field was developed from comparative psychology. It has also been strongly influenced by research in ethology, behavioral ecology, and evolutionary psychology; the alternative name cognitive ethology is sometimes used. Many behaviors associated with the term animal intelligence are also subsumed within animal cognition.

Researchers have examined animal cognition in mammals (especially primates, cetaceans, elephants, bears, dogs, cats, pigs, horses, cattle, raccoons and rodents), birds (including parrots, fowl, corvids and pigeons), reptiles (lizards, crocodilians, snakes, and turtles), fish and invertebrates (including cephalopods, spiders and insects).

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large reptile of the monitor lizard family Varanidae that is endemic to the Indonesian islands of Komodo, Rinca, Flores, Gili Dasami, and Gili Motang. The largest extant population lives within the Komodo National Park in Eastern Indonesia. It is the largest extant species of lizard, with the males growing to a maximum length of 3 m (10 ft) and weighing up to 150 kg (330 lb).

As a result of their size, Komodo dragons are apex predators, and dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. Komodo dragons' group behavior in hunting is exceptional in the reptile world. The diet of Komodo dragons mainly consists of Javan rusa (Rusa timorensis), though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans.

Mosasaurus (/ˌmoʊzəˈsɔːrəs/; "lizard of the Meuse River") is the type genus (defining example) of the mosasaurs, an extinct group of aquatic squamate reptiles. It lived from about 82 to 66 million years ago during the Campanian and Maastrichtian stages of the Late Cretaceous. The genus was one of the first Mesozoic marine reptiles known to science—the first fossils of Mosasaurus were found as skulls in a chalk quarry near the Dutch city of Maastricht in the late 18th century, and were initially thought to be crocodiles or whales. One skull discovered around 1780 was famously nicknamed the "great animal of Maastricht". In 1808, naturalist Georges Cuvier concluded that it belonged to a giant marine lizard with similarities to monitor lizards but otherwise unlike any known living animal. This concept was revolutionary at the time and helped support the then-developing ideas of extinction. Cuvier did not designate a scientific name for the animal; this was done by William Daniel Conybeare in 1822 when he named it Mosasaurus in reference to its origin in fossil deposits near the Meuse River. The exact affinities of Mosasaurus as a squamate remain controversial, and scientists continue to debate whether its closest living relatives are monitor lizards or snakes.

The largest species, M. hoffmannii, is estimated to measure up to 12 meters (39 ft) in maximum length, making it one of the largest mosasaurs. The skull of Mosasaurus had robust jaws and strong muscles capable of powerful bites using dozens of large teeth adapted for cutting prey. Its four limbs were shaped into paddles to steer the animal underwater. Its tail was long and ended in a downward bend and a paddle-like fluke. Mosasaurus possessed excellent vision to compensate for its poor sense of smell, and a high metabolic rate suggesting it was endothermic ("warm-blooded"), an adaptation in squamates only found in mosasaurs. There is considerable morphological variability across the currently-recognized species in Mosasaurus—from the robustly-built M. hoffmannii to the slender and serpentine M. lemonnieri—but an unclear diagnosis (description of distinguishing features) of the type species M. hoffmannii led to a historically problematic classification. As a result, more than fifty species have been attributed to the genus in the past. A redescription of the type specimen in 2017 helped resolve the taxonomy issue and confirmed at least five species to be within the genus. Another five species still nominally classified within Mosasaurus are planned to be reassessed.

The endongo is a musical instrument, considered the national instrument of the Baganda people of Uganda. It is a member of a family of lyres which can be found, with variations, in many areas throughout East Africa. The endongo is specifically a Kiganda bowl lyre, with the face of the bowl covered with the skin of either a monitor lizard or ant lizard.

The endongo is found within the interlacustrine area of Uganda, which are “the kingdom-states around the northern, western, and southern shores of Lake Victoria and the area between Lake Victoria and the chain of lakes: Lake Albert, Lake Edward, Lake Kivu and Lake Tanganyika”. The bowl lyre present in Uganda is played by two particular tribes, the Basoga, who name the instrument entongoli, and the Baganda, who call it the endongo.

The Dampier Peninsula monitor or Dampier Peninsula goanna (Varanus sparnus), described in 2014, is the smallest known species of monitor lizard, growing up to 16.3 grams with a length of almost 23 cm and a SVL (snout to vent length) of 116 mm. It is believed to live only on the Dampier Peninsula of the Kimberley region north of Broome and Derby in Western Australia. It is highly active, making it difficult to photograph in the wild. It has short legs, an elongate body, a reddish-brown back with widely scattered black spots and "a ridged, circular and short prehensile tail."

Megalania (Varanus priscus) is an extinct species of giant monitor lizard, part of the megafaunal assemblage that inhabited Australia during the Pleistocene. It is the largest terrestrial lizard known to have existed, but the fragmentary nature of known remains make estimates highly uncertain. Recent studies suggest that most known specimens would have reached around 2–3 m (6.6–9.8 ft) in body length excluding the tail, while some individuals would have been significantly larger, reaching sizes around 4.5–7 m (15–23 ft) in length.

Megalania is thought to have had a similar ecology to the living Komodo dragon (Varanus komodoensis) which may be its closest living relative. The youngest fossil remains of giant monitor lizards in Australia date to around 50,000 years ago. The indigenous peoples of Australia might have encountered megalania when they first arrived on the continent and might have subsequently played a role in megalania's extinction. While originally megalania was considered to be the only member of the titular genus "Megalania", today it is considered a member of the genus Varanus, being closely related to other Australian monitor lizards.

Varanopidae is an extinct family of amniotes known from the Late Carboniferous to Middle Permian that resembled monitor lizards (with the name of the group deriving from the monitor lizard genus Varanus) and may have filled a similar niche. Typically, they are considered to be relatively basal synapsids (and thus more closely related to mammals than to reptiles), although some studies from the late 2010s recovered them being taxonomically closer to diapsid reptiles, recent studies from the early 2020s support their traditional placement as synapsids on the basis of high degree of bone labyrinth ossification, maxillary canal morphology and phylogenetic analyses. A varanopid from the late Middle Permian Pristerognathus Assemblage Zone (Capitanian) is the youngest known varanopid and the last member of the "pelycosaur" group of synapsids. Thus, Varanopidae vanishes from the fossil record at the same time as dinocephalians, plausibly as a result of a major mass extinction event that has been called the "Dinocephalian extinction event".