Information sheet about marine animals seen underwater in the Galapagos
(approx. 7 pages)

Endemic Fishes of the Galapagos - Galapagos main page - west - north and northeast - center - southeast

Endemic species

In the pages about the Galapagos islands, the word "endemic" is often used to describe a species that only occurs on these islands. Endemic animals or plants are restricted to a particular geographic region and found nowhere else in the world. Endemism usually occurs in areas that are isolated in some way. Since the Galapagos were never connected to the mainland which lies 960km away, all species had to reach the islands either by swimming (fish, sea lions etc.), by flying (birds, insects etc.) or on rafts (land animals, mammals, reptiles etc.). Once here they evolved and occupied different ecological niches. The endemic species in the Galapagos are specially adapted to the harsh conditions on the archipelago like the scarcity of fresh water, the availability of only certain food and the dark volcanic rocks.

Conditions for marine animals

Marine life in the Galapagos is very rich, though not so varied as in warmer tropical waters. Due to the cold water there are only a few species of corals and those grow mostly in the subtidal zone. There are nice reefs near Floreana (Devil's Crown, Onslow island), Bartolomé Island, Champion island and Wolf and Darwin.

In the warm season (from December to May), the chance to see whale sharks is very high (in the northern islands), and you can also observe them in the central islands. In the cold season (May to December) the chance to see whale sharks is about 50 percent, and you see more rays like mantas, mobula, and eagle rays, since they get together in schools to mate. Hammerheads can be found throughout the Galapagos Archipelago year-round. The large schools of fish, sea turtles, sea lions, iguanas and penguins are also found during the whole year


Jack Grove and Robert J. Lavenberg have documented 444 fish species in 112 families with 9.2% endemic species (= restricted to a particular geographic region and found nowhere else in the world). From the 41 endemic species, most are blennies and stargazers (11 species Blennioidei) and small fishes of the family Percoidei like grunts and drums (10 species) and brotulas (6 species Ophidiformes) and a few gobies and eels. The endemic fishes are mostly small fish, that live close to the shore.

Since the Galapagos are surrounded by deep ocean, there are also a lot of pelagic fishes found here, several species of sharks like whale sharks, white tipped sharks, Mako, thresher sharks, several species of requiem sharks, hammerhead sharks, Galapagos shark, Galapagos horned shark as well as rays, mantas, eagle rays, mobulas, tunas, jacks, Marlin swordfishes and even the huge sunfishes (Mola mola and Ranzania laevis).

Sharks seen in the Galapagos islands

The whale shark (Rhincodon typus / español: tiburón ballena / Deutsch: Walhai) is with up to 12m the world's largest shark. Its color is gray with a pattern of spots and bars. It has an enormous mouth and feeds on zooplankton, pelagic crustaceans, small fishes and squids which are sieved through a spongy tissue between the gill arches. Found in tropical and temperate waters around the world, seen mostly in areas of upwelling. Photos on starfish

The most common hammerhead shark around Wolf and Darwin is the scalloped hammerhead, although the smooth and the great hammerhead have also been recorded on Galapagos. They differ from the shape of their head and dorsal fin and their size.

The scalloped hammerhead shark (Sphyrna lewini / español : tiburón martillo / Deutsch: Bogenstirn Hammerhai) is up to 2.5m long, gray color and is distinguished by having the eye and nostril very close together and having a head with three lobes or indentations. This pelagic sharks usually forms large schools and feeds primarily on fishes, occasionally on cephalopods and crustaceans. Found in tropical waters around the world. Photos on starfish

The smooth hammerhead shark (Sphyrna zygaena / español: Cachona / Deutsch: Gewöhnlicher Hammerhai) can be 2.5 to 3.5m long, gray color and no indentations. Feeds on cephalopods and fishes as well as rays and small sharks. Found in tropical to temperate waters around the world.

The great hammerhead shark (Sphyrna mokarran / español: Gran tiburón martillo / Deutsch: Grosser Hammerhai) can reach 5.5m length. The leading edge of the head is nearly strait and he has a very high and pointed dorsal fin. Rare on most coral reefs. Feeds primarily on fishes, particularly rays and small sharks, occasionally on cephalopods and crustaceans. Found in tropical to temperate waters around the world.

The Galapagos shark (Carcharhinus galapagensis / español: tiburón de Galapagos / Deutsch: Galapagos Hai) is not endemic to the Galapagos though common in the island and often seen in loose groups. It can be from 2.5 up to 3.5m long, gray-brown above, yellow-white beneath, with long pectoral fins. They feed on sea lions and marine iguanas. Common around islands in the eastern Pacific.

The silky shark (Carcharhinus falciformis / español: tiburón jaquetón / Deutsch: Seidenhai) is infrequently encountered in the Galapagos. They are slender with their first dorsal fin well behind the pectoral fins, dark gray to gray-black, can be over 3m long. Seen together with other species of sharks when hunting. They feed mainly on large fish. Silky sharks are pelagic and widely distributed in the tropical eastern Pacific.

The endemic Galapagos bullhead shark (Heterodontus quoyi / español: gato / Deutsch: Galapagos Stierkopfhai), a bottom dwelling relatively small gray-brown shark with black blotches. It feeds primarily on shellfish, crabs and other crustaceans. This shark has a box-shaped head with a large ridge over the eyes and a sharp spine (horn) at the front of both dorsal fins. This shark is locally also known as Port Jackson horned shark, although the real Port Jackson shark (H. portusjacksoni) only lives in western Australia. Often seen at night.

Some of the common schooling fishes

The Pacific Creole fish (Paranthias colonus or five spot anthias / español: Gringo) is probably the most common fish in the entire archipelago. It is olive to gray below and copper red above and has 3 or 5 white or dark spots on the back and the base of the deeply forked tail. Juveniles are yellow with blue markings under their eye and intermediates have a dark, ringed spot. They form huge aggregations in open water or above rocks where they feed on small fishes and plankton. They are an important source of food for the blue-footed boobies. About 35 cm. Photos on starfish

The King Angelfish (Holacanthus passer / español: Pez bandera / Deutsch: Kaiser von Mexico) is dark blue or black with a white vertical bar. Females have yellow pectoral fins, males white ones. Like with other angelfishes, the juveniles are colored differently, orange or hazel brown with blue vertical stripes and yellow pectoral fins. They also live north to Panama and Costa Rica and Baja California. King angelfishes are seen in the Galapagos often while cleaning larger fishes like hammerheads or mantas. They pick various parasites off them. They also feed on algea and small invertebrates. About 25 to 30cm. Photos on starfish

The Blacknosed Butterflyfish (Johnrandallia nigrirostris / español: Mariposa barbero / Deutsch: Putz-Falterfisch) is a small butterflyfish (13cm) found in the eastern Pacific. Likes rocky reefs down to 40m, mostly in large schools. The blacknosed butterflyfish gathers at cleaning stations, where they clean other fishes, picking off parasites from their skin. This kind of behavior I have also seen with bannerfishes (a relative of the butterflyfishes) in Lembongan, Indonesia, where they clean sunfishes. Photos on starfish

The Yellowtailed Surgeonfish (Prionurus laticlavius or razor surgeonfish / español: Chancho / Deutsch: Galapagos Sägedoktor) is only found in the East Pacific. This is the most common surgeonfish in the Galapagos, gray to silvery with small black dots and two dark stripes around the eyes and a yellow tail with three retractable spines at the base. They are seen in large schools usually in shallow water. Juveniles are yellow and also school. Feed on algae attached to rocks. About 46cm. Photos on starfish

There are several species of grunts common to the islands with three endemic species: the White Salema (Xenichthys agassizi) and the Blackstriped Salema (Xenocys jessiae / español: ojón / Deutsch: Grunzer) which are quite common. Salemas are an impressive sight, since they form immense schools above rocky reefs, sandy areas and slopes. Photos on starfish

The endemic Galapagos Grunt (Orthopristis forbesi / español: Roncador de Galapagos / Deutsch: Galapagos Grunzer) is rarely seen, but has been recorded on Fernandina. It has large silvery scales with dark markings. They school above rocky, boulder strewn reefs and slopes.

The Golden-eyed Grunt (Haemulon scudderi) and the yellowtail grunt (Anisotremus interruptus - Burrito - Yellow-tailed grunt) are also very common, but not endemic. They school above rocky reefs or sandy areas and slopes.

Other fishes

Another fish endemic to the Galapagos is the White-spotted Rock Sea Bass (Paralabrax albomaculatus / español: Camotillo), a sea bass with a row of white spots on the side. This fish is common around Isabela and likes cold water, so it is found mostly in areas of upwelling where it feeds onsmaller fish. Length about 25cm.

Another sea bass is the Sailfin Grouper (Mycteroperca olfax, español: Bacalao) which is common around the entire archipelago. While it usually is of a gray or brown color, it can also be bright golden yellow. These are known as bacalao rey (king bacalao). This is the economically most important fish in the Galapagos. They prefer open water near walls. Can grow to 1m long.

The Harlequin Wrasse or Galapagos hogfish (Bodianus eclancheri / español: vieja mulata ) is an interesting looking multicolored wrasse. Not one fish looks like the other, they have various designs of orange, black, white and yellow. Most have a white chin patch and all a black spot at the base of the pectoral fins. Large adults have a distinctive bump on their forehead. They prefer cold water and are thus more common on the western islands. Another hogfish with a distinctive bump is the Mexican hogfish (Bodianus diplotaenia) which has longish fins and is gray to green-blue. Photos on starfish

The Goldrimmed Surgeonfish (Acanthurus nigricans or whitecheek tang / español: Pez cirujano de filo amarilla / Deutsch: Goldrand-Doktorfisch oder Samtdoktor) is mostly found around Isabela, Darwin and Wolf and is uncommon in the remainder of the archipelago. They are dark blue with a white tail and elongate white spot directly below eye. They inhabit clear lagoon and seaward reefs. They are herbivores and feed on filamentous algae. About 21cm.

There are two species of sunfish found in the Galapagos, the ocean sunfish (Mola mola / español: Pez luna / Deutsch Mondfisch) and the slender Mola (Ranzania levis). Punta Vicente Roca is one of the dive sites with sunfish sightings as well as Gordon's Rock, North Seymour, Española and the south of Isabela. The sunfish is the largest bony fish and can be up to 3m in length. I have seen this fish many times during the cold season in Lembongan, Bali, Indonesia, where it approaches the reef to get cleaned by angelfishes. The sunfish has a very unmistakable look with its eccentric roundish shape with huge fins but nearly no discernable tail and wont be mistaken for a shark or ray. Photos on starfish

The Pacific seahorse (Hippocampus ingens / español: Caballito de Mar del Pacífico / Deutsch: Pazifisches Seepferdchen) is the only seahorse in the eastern Pacific. It has very variable colorings, from reddish to gray, yellow, gold and various shades of brown. Around their eyes they have streaks and lines radiating. Adults have white light and dark markings. They are well camouflaged and are often found among black coral bushes and gorgonians or with their tail around seagrass. They feed on small crustaceans and zooplankton which are siphoned into their tubelike mouth. Although they are seen on reefs around corals, it seems that this seahorse spends a lot of its life in the open sea. About 24 to 29cm. Photos on starfish

There are 3 species of frogfishes living in the Galapagos, Antennarius sanguineus (Bloody frogfish / español: pejerana bandeado), Antennarius avalonis (Roughbar frogfish / español: pejerana colorado), the small Antennatus strigatus (Bandtail frogfish / español: pejerana bocon) which all have been collected around Fernandina. All are rarely seen and hide well among the rocks.

Bottom dwelling fishes

A weird looking fish which is found here is the red-lipped batfish (Ogcocephalus darwini / español: Pez murcielago labio rojo / Deutsch: Rotlippen-Fledermausfisch). As it's name suggests it has bright red lips and is about 17cm large. Walking batfishes have modified fins, that are used to walk (or rather hop) across the sea floor. They only swim occasionally and in a rather cumbersome fashion by spreading their pectoral fins. Like the frogfish (they also belong to the order of Lophiiformes) they have a modified first dorsal spine with a long rod (illicium) and an attached lure (esca). This rod is usually tucked into a depression above the mouth. Feeds on small invertebrates like crabs and mollusks. The snout of batfishes varies in shape and length, when they grow, it becomes smaller and more knob like. Red lipped batfishes usually live on sand, rubble or rocky bottoms from 3 - 76 m. Common in the entire Galapagos archipelago, active at night. Photos on starfish

There are 3 species of frogfishes in the Galapagos, Antennarius sanguineus (Bloody frogfish - pejerana bandeado), Antennarius avalonis (Roughbar frogfish - pejerana colorado), the small Antennatus strigatus (Bandtail frogfish - pejerana bocon). Unfortunately I haven't seen any on my trips yet (still hoping). Frogfishes are diffcult to find, because often they are perfectly camouflaged, showing the same colours as the sponges or the ground they sitting on. Frogfishes have converted one of the drosal fins into a lure. The lures mimic food animals like worms, small shrimps or small fish. The prey approaches to eat the lure and then is engulfed by the waiting frogfish. Frogfishes mainly eat fishes and crustaceans (shrimps and crabs). They can swallow items of prey that are twice as large as them.

The Zebra moray eel (Gymnomuraena zebra / español: morena zebra / Deutsch: Zebra Muräne) which is uncommon in the entire archipelago is also found here. This moray has an unique black and white color pattern which gives it its name. The snout of the zebra moray is very blunt with pebble-like teeth, so it can feed on large, heavily armored crabs and other crustaceans as well as snails and sea urchins. With the large crabs it will crush the claws and walking legs, with smaller crabs the entire animal. Hunts in reef crevices and rarely ventures out into the open. Length 88cm.

On sandy areas there are fields of the endemic Galapagos garden eels (Heteroconger klausewitzi). They are dark brown with a row of white spots on the sides of the body and some irregular patches. These eels inhabit sandy areas where there is some current, so they can feed on zooplankton, that drifts past their burrows. Like all garden eels they tend to be shy and retreat into their holes when approached. About 44cm. Also found in Mosquera, Plazas islands and Devils' crown.


The endemic marine iguana (Amblyrhynchus cristatus / español: iguana marina / Deutsch: Meeresechse) forms large colonies. Marine iguanas can get over a meter in length and can weight close to 9kg. They represent the only species of truly marine lizards. They are vegetarians and feed almost exclusively on marine algae. Marine iguanas are excellent swimmers, using their flattened tail and dive down to depths of 12m to nip the algal tufts from the rocks. It is amazing, that the thousands of iguanas (an estimate is of 250'000 animals, 7 subspecies) don't eat the rocks bare of algae. However the algae grow back quite fast, specially in the nutrient rich waters of the west. After diving the iguanas gather in large numbers and bask on the volcanic rocks so they can warm up in the sun. With the algae they ingest a lot of salt. They have adapted to this and have salt glands above each eye connected by a duct to the nostril. You can observe how the salt is literally sneezed out! Photos on starfish

There are also marine turtles around Galapagos, the green turtle and the hawksbill turtle. The green turtles here on the Galapagos are unusual dark, probably to better absorb the warmth of the sun in this cold water. The breeding season is during the warmer time of the year.


There are many sea birds living on the Galapagos und while diving or snorkeling you will encounter them sometimes, while they search for food. Of interest for the diver is the endemic Galapagos penguin, the flightless cormorant and the boobies which all can be encountered underwater while diving.

Boobies belong to the family Sulidae. In the Galapagos, there are three species of boobies: the red-footed booby, the blue-footed booby and the Nazca booby (formerly Masked booby). They have a similar body shape and are differated by the color of their completely webbed feet and their size. You can distinguish males from females by voice - males whistle and the females honk.

The blue footed booby (Sula nebouxii / español: piquero patas azul / Deutsch: Blaufusstölpel) is mostly found at the center and edges of the archipelago (Española, Daphne, and North Seymour). As the name suggests they have amazing blue feet. Females have a ring of dark pigment around their pupils, making them look bigger than those of the males. Courtship, mating and nesting occur year round. The blue-footed boobies nest on the ground and often make a guano ring around the nest area. They lay up to three eggs and in a good year they can raise all three chicks. Blue-footed boobies fish very close inshore in shallow water. Boobies are plunge divers and their dive is spectacular. They have good eyes and can spot fish from about 10m up and then dive down into the water with their wings folded back. You often see small groups of boobies flying in formation looking for fish. If you are lucky can see them underwater while you are diving! Photos on starfish

The red-footed booby (Sula sula / español: piquero patas rojo / Deutsch: Rotfusstölpel) have red feet and a blue bill with a red base. It is actually the most numerous of the Galapagos boobies, but since it lives at the outlying islands (Genovesa and Punta Pitt - see above) it also is the least frequently seen. Red-footed boobies fish well out at sea and thus always are gone for a while. This is probably the reason why of the boobies on Galapagos only the red-footed booby builds nests in trees. They lay only one egg and raise one chick. This usually happens when there is plenty of food and can occur at any time in the year. The red-footed booby is with about 74cm the smallest.

The Nazca booby (Sula granti - formerly Sula dactylatra grand / español: piquero enmascarado / Deutsch: Nazca Maskentölpel) is pure white with a black band at the edges of the wings and the end of the tail. They have a yellow or pinkish bill and there is a blackish area of bare skin surrounding the bill which looks like a mask. They are found on most islands (good places are Genovesa, Española, Daphne). Nazca boobies fish a bit farther out than blue-footed boobies. They have an annual breeding cycle. They nest near cliffs on the ground and lay two eggs, several days apart, so the older chick is much bigger than the younger. If the older chick survives, it will push its younger sibling out of the nest. However if the older chick dies, there is still a chance, that the younger chick will survive. With about up to 89cm it is the largest of the Galapagos boobies. Nazca boobies were formerly regarded as a subspecies of the Masked Booby (Sula dactylatra) but the Nazca Booby is now recognized as a separate species.

The endemic flightless cormorant (Nannopterum harrisi / español: cormorán áptero / Deutsch: Flugunfähiger Kormoran) is only found on the coastline of Fernandina and the northwestern shore of Isabela where the cold Cromwell current upwells. It is very large for a cormorant (about 90cm), brown with a long beak, very small wings and very large feet. It is the only cormorant in the Galapagos, and it is the only cormorant that has lost the ability to fly. The birds feed near the shore and near the bottom on squid, octopus, eel, and benthic fish. While diving for food it propels itself by powerful kicks of its large legs. When they return from a hunting trip offshore, they must open up their wings to dry them out. This looks a bit strange, since their wings are so small. It should be possible to see them underwater while diving, though I have heard, that you are not allowed to dive at some dive areas around Fernandina anymore.

Galapagos penguins (Spheniscus mendiculus) are the second smallest penguins in the world and the only species also found north of the equator. Standing up they are about 35cm high, the total length is about 50cm. On land they are very slow and clumsy. But underwater they are very interesting to observe, they always leave a visible track of bubbles behind them and move at incredible speeds. Penguins have a very special swimming style. Using their wings as flippers they literally zip around the water, they are able to make sharp turns, swim in zigzag and even make flips. The Galapagos penguin is mainly found in the western islands where the water is cooler, but also around Santiago and Floreana. They breed at any time during the year, their clutch is two eggs, but most times only one will survive. Photos on starfish


On most islands live Galapagos sea lions. They are excellent swimmers and will be encountered often underwater. The endemic Galapagos fur seal are less commonly seen. Whales and Dolphins are encountered when cruising between the islands. A lot of cetacean sightings were at the western side of Isabela, where the water is colder.

There are two species of pinnipeds living on the Galapagos islands - the Galapagos fur seals (Arctocephalus galapogoensis / español: Lobo de dos pelos or lobo fino / Deutsch: Pelzseelöwe oder Galapagos-Seebär) and the Galapagos sea lions (Zalophus californicum wollebacki / español: lobo de mar / Deutsch: Galapagos-Seelöwe). Actually the name "fur seal" is misleading, since they are not true seals but also sea lions, the correct name should be fur sea lion. Photos on starfish

The Galapagos islands lie on the equator and actually these two species of pinnipeds have reached the islands coming from very different directions. Fur seals are believed to have come from the south (their ancestor is the south American fur sea lion) and sea lions came from the north (their close ancestor is the Californian sea lion).

They differ by their size - the fur seal is smaller and more compact with large eyes and ears that stick out noticeably. Fur seals have a thick, dense coat consisting of two layers, an outer layer of long hairs and an inner one of short dense fur (thus the name fur seal). This thick fur is of course a relict from their origins in cold southern water and it was the reason why they were hunted nearly to extinction before the Galapagos island became a National Park. Fur seals have a broader head, whereas sea lions have a pointed head.

Fur seals feed primarily on fish and cephalopods, close to shore and exclusively at night when their prey migrates closer to the surface. Breeding time is between mid-August and mid-November, most pups being born between late September and early October.

Sea lions normally dive down quite deep, from 20 to 70m. They are often seen where large schools of their preferred prey, sardines are. Breeding time is from May - January. Watch out for the male sea lions, they may bite.


Sea cucumbers, sea urchins, crabs and shrimps, sponges and anemones live in the water around the Galapagos. There are several endemic species, such as the Galapagos black corals, cup corals or the 3 species of sea slugs as well as some species of crabs, chitons, scallops and sea stars.

Molluscs: There are over a hundred species of Mollusks found in the Galapagos, about 18% of the shallow water mollusks are endemic. Among them are several nudibranchs that are probably endemic to the Galapagos islands. The starry night nudibranch (Hypselodoris lapislazuli) has a dark blue body with yellow dots. Creme to brown colored border and gills. Length 3 to 5cm. Feeds on sponge. The Ruzafa Doris (Chromodoris ruzafai) has a pale-blue body with irregular reddish band marked with yellow spots. Pink gills and dark brown rhinophores. The blue-striped sea slug (Tambja mullineri, also called Mulliner Doris) has turcoise-blue stripes with dark blue rhinophores and gills, 2 to 4 cm large. The Carolyn Doris (Platydoris carolynaeare) has a flattened cream colored body with black and brown pigment and a large elongate black spot on the back with dark rhinophores and gills. There is also two species of intertidal slugs (living in estuarine mangroves or on rocky coasts), lung breathing dark colored oval slugs, which are endemic to the Galapagos. Photos on starfish

There are more nudibranchs living here, such as Robastra, Flabellina marcusorum, Aplysia cedrosensis, Aeolidiella indica and A. alba, Berthellina engeli, Cadlina sparsa, Hypselodoris agassizii. They are not endemic, but also found around the east Pacific coast (Costa Rica, California).

Many octopuses (Octopus oculifer and other species) are found in the rocky areas. It is worth to take a close look at the rocks because although they might sit in plain view, they are so well camouflaged, that they are easily overlooked. they seem to be not very shy and when we found one, it was moving slowly around and didn't hide straight away as I am used to from tropical water. So called paper nautilus or argonauts (Argonauta pacificus) can also be found on the Galapagos and flying squids (Sthenoteuthis ovalaniensis) are common food for birds. Photos on starfish

Corals: The Galapagos black coral (Antipathes galapagensis) is actually of yellow color and builds large bushes. It is called black, because when dried, the internal skeleton has a black color. Black coral is harvested commercially and used for jewelry and and thus is often overexploited. Black coral is a soft coral and does not form a corallite. Most of black coral in the Galapagos were not affected by the 1982 / 83 El Niño event, because they live not so close to the surface. There are also a lot of tube corals living here, which are also called popcorn corals. The orange cup coral (Tubastrea cocinea) and the pink cup coral (Tubastrea tagusensis), gorgonians sea fans as well as the small Mexican anemones (Bunodactis mexicana) and some tube corals (Pachycerianthus fimbriatus) grow around the Galapagos. Photos on starfish

Other invertebrates: The most well known crab is the sally lightfoot crab (Grapsus grapsus) who lives on the shores of all islands. They are scavengers and feed on almost anything. They climb over the lizards and groom them, eating parasites and algae growing on the skin. Of course there are also a lot of hermit crabs and shrimps as well as slipper lobsters and other lobsters. You will also often find several different species of sea stars and sea cucumbers. There are pencil urchins (Eucidaris thouarsii) which eat corals or toxic sea urchins like Toxotneustes roseus. Photos on starfish

In Tagus Cove you can also find the largest species of asteroids in the world, Luidia superba or giant sea star. This five-armed starfish is over 1.2m large and preys on other starfishes. It hadn't been seen for several years and was rediscovered in 1974. The family of Luidiidae contains quite a lot of large sea stars with 5 to 15 arms. They usually burrow in sand.

Recommended book:
Paul Humann, Reef Fish Identification, Galápagos, 1993
Pierre Constant, Marine Life of the Galápagos, 2002
Jack Grove and Robert J. Lavenberg, The Fishes of the Galápagos Islands, 1997
Matthew J. Jones, Galápagos Marine Invertebrates, 1991

This page www.starfish.ch/scubadiving/print/Galapagos-marine-animals-print.html . Copyright Teresa Zubi (write to me).
I am not responsible for the contents of any sites linked to this website or any other off-site pages. Link to them at your own risk.