Mammals of North America

by Roland W Kays

  NORTHERN RIGHT WHALE DOLPHIN Lissodelphis borealis 2–3.1m; 2–2.6mm, 60–113kg

  Our only slender, beaked dolphin without a dorsal fin. All other dark dolphins have blunt faces and obvious dorsal fins. Dark color is broken up by white on lower jaw, chest, belly, and under the fluke. Calves are grayish brown or cream-colored. Jumps with low-angle leaps. Dive up to 200m in search of fish and squid, and capable of speeds up to 34km per hour. Widely distributed and relatively abundant in deep waters of the Pacific, where they form herds of hundreds or even thousands of individuals.

  PLATE 105

  STRIPED, BEAKED DOLPHINS

  SPINNER DOLPHIN Stenella longirostris 1.3–2.4m, 22–75kg

  Characterized by spinning leaps, this species has a long, thin beak. The only other spinning dolphin, Clymene, has a shorter beak. Color may be dark “battleship” gray, or tricolored with a darker back and white belly. Some gray animals have white patches on belly. Stripe between eye and flipper is parallel (not triangular). Dorsal fin becomes more erect with age. Males have a large post-anal hump. Single 0.75m calf born after gestation of 10.5 months. Lactation lasts 1–2 years. Association with schools of tuna leaves them vulnerable to suffocation in tuna nets. Swims in groups of up to 200, sometimes with other species, in warmer Atlantic waters and south of Baja California in the Pacific.

  CLYMENE DOLPHIN Stenella clymene 1.8–2.0m, 50–85kg

  A tricolored spinning dolphin with a relatively short beak. Stripe between eye and flipper is triangular (not parallel). Often has white “moustache” on upper mandible. Tail stock of males is usually keeled. Smallish, curved dorsal fin is sometimes marked with pale coloration. Groups of up to 50, often mixed with other dolphin species, feed on fish and squid. Found in warm Atlantic and Caribbean waters, where it is rarely seen.

  STRIPED DOLPHIN Stenella coeruleoalba 8–2.5m, 110–156kg

  Unique with dark eye-to-anus stripe and a pale marking below dorsal fin. Typically grayish, but may include blue or brown tones. Belly is white or pink. Specific stripe pattern is variable, but most originate from the eye. Feeds on fish, shrimp, and squid. Known for “roto-tailing,” rapidly rotating the tail while leaping out of the water. Groups of 10–500 use deep water along both coasts.

  SHORT-BEAKED COMMON DOLPHIN Delphinus delphis 1.7–2.2m; 1.6–2.2m, 70–110kg

  A short-beaked dolphin with yellow and gray hourglass coloration. The four-part hourglass color scheme includes dark back, white belly, yellowish flanks, and a gray tail stock. Yellow may appear pale gray at sea. The variable flipper stripe typically originates with a zigzag near the middle of the lower mandible. Has a more rounded head and more contrasting colors than Long-beaked Common Dolphin, including a dark eye patch. There is considerable variability in the pattern of the colors and stripes. Common along both coasts in schools of from 10 to several thousands.

  LONG-BEAKED COMMON DOLPHIN Delphinus capensis 2–2.5m; 1.9–2.2m, 70–135kg

  A long-beaked dolphin with hourglass coloration. Flipper stripe typically originates near the corner of the mouth. Has a more sloping head profile than D. delphis, and more muted colors. Feeds on fish, but likely also takes deep-water squid. Young born in spring and summer. Groups of 10–500 found off southwestern coast.

  PLATE 106

  STRIPED, BLUNT-NOSED DOLPHINS AND PORPOISES

  PACIFIC WHITE-SIDED DOLPHIN Lagenorhynchus obliquidens 1.7–2.5m, 75–200kg

  Blunt-nosed dolphin with three-part color pattern and black beak. Back is dark gray, sides are streaked light and dark gray, belly and chin are white. Dorsal fin and flippers also colored with light and dark gray. Not shy of boats. Gregarious, active swimmer in offshore waters of the Pacific, sometimes associates with other dolphins or seals.

  FRASER’S DOLPHIN Lagenodelphis hosei 2.3–2.7m; 2.1–2.6mm, 164–209kg

  Short-beaked dolphin with a pair of broad, straight stripes running from eye to tail stock. Back is gray, belly is creamy white or pink. Thin, dark flipper stripe connects to beak. Dorsal fin and flippers are small. Sometimes associated with other dolphins. Rarely sighted off Caribbean coast.

  ATLANTIC WHITE-SIDED DOLPHIN Lagenorhynchus acutus 2.3–2.8m; 1.9–2.4mm, 180–230kg

  Unique with short beak and yellow patch on tail stock. Back is black, belly white, and flanks are gray with white and yellow patches. Thin black flipper-stripe starts from corner of mouth. Lower mandible is all white. Swims in groups of 5–50 in the North Atlantic.

  WHITE-BEAKED DOLPHIN lagenorhynchus albirostris 2.5–3.1m; 1.8–2.4m, 180–354kg

  Dark, robust-bodied dolphin with a white blaze on flanks and pale patch on tail stock. Head is dark gray, short beak and throat are white. Beak may be marked with brown or gray. Found in groups of up to 30 in North Atlantic, especially along edge of continental shelf.

  PORPOISES - A group of small, blunt-nosed dolphins. Two species are known from our waters, mostly near the coast.

  HARBOR PORPOISE Phocoena phocoena 1.5–1.9m, 45–90kg

  Small gray porpoise with no beak. Lips and back are dark, throat and belly are white. Flippers are small and rounded. Wispy, dark flipper stripes. Shy and hard to watch. Swims in small groups of two to five near shore along western and northeastern coasts.

  DALL’S PORPOISE Phocoenoides dalli 1.8–2.3m, 84–114kg

  Unique blunt-faced porpoise boldly patterned with black and white. Fluke and dorsal fin also colored with black and white. Male is slightly larger and has a hump behind dorsal fin. Female has a black trident pattern in genital area. Active and unpredictable swimmer, frequently creates “rooster tail” splashes. Common in the Pacific.

  PLATE 109

  BEAKED WHALES

  BEAKED WHALES - A diverse group of whales that are recognizable by their spindle-shaped bodies and small, posteriorly positioned dorsal fins. These shy inhabitants of deep waters are poorly known and difficult to identify at sea. Some are known only from rare strandings. Body color of live animals is often variable and/or unknown. The male’s remarkable tooth morphology is often the key to identification, as well as the cause of their extensive scarring.

  TRUE’S BEAKED WHALE Mesoplodon mirus 5.0–5.3m, ca. 1400kg

  Male has two small teeth erupting from the front of beak (see page 232). Has straight mouthline. Medium-gray back, pale underside, scarring throughout. Flippers can be tucked away in “pocket” on underside. Known to feed on squid. Some 16 records known off Atlantic coast.

  STEJNEGER’S BEAKED WHALE Mesoplodon stejnegeri 5.2m, ca. 1100kg

  Large tooth erupts from peak of the curved lower mandible in male (see page 232). Females have a less curved mouthline. Gray to black in color, often with light patches on beak, head, and neck. Scarring throughout. Stomachs of stranded individuals contained only squid. Some 41 records in deep Pacific waters, mostly off Alaska. Groups of 5–15 individuals have been recorded.

  NORTHERN BOTTLENOSE WHALE Hyperoodon ampullatus 9.0–9.5m, 10,000kg; 8.0–8.5m, ca. 7500kg

  Large whale with a relatively small beak protruding from bulbous head. Dorsal fin is two-thirds of the way down the body. Dark gray to brownish body color. Forehead is most bulbous in the males, with two teeth protruding from tip of lower jaw. Older males are pale gray or white on head and neck. Light crescent sometimes present on neck. No center notch in fluke. Small groups (up to 10) found in North Atlantic.

  BAIRD’S BEAKED WHALE Berardius bairdii 10.7–12.8m, 6800–14,200kg

  Large beaked whale with long narrow rostrum and a bulging forehead. Longer beak and smaller forehead than in the Bottlenose Whale. Males have a more bulbous head and teeth erupting from tip of lower jaw. Gray body marked with white spots on underside and scars throughout. Small dorsal fin located far back on tail stock. Center fluke notch is small or absent. Capable of diving to 1000m and staying down for 2 hours. Groups of 3–30 in Pacific Ocean.

  CUVIER’S BEAKED WHALE Ziphius cavirostris 5.1–6.9m, ca. 2500kg

  Robust, cigar-shaped whale with a short, poorly defined beak mark
ed with two small teeth at the tip in males. Teeth sometimes covered in barnacles. Mouthline is short and upturned. Color varies from rust brown to slate gray, belly is usually lighter. Has scarring throughout. The head of males grows whiter with age. No medial notch in fluke. Small dorsal fin about two-thirds of the way back from snout. Common and widespread in both oceans, but rarely seen.

  PLATE 110

  HEADS OF MALE MESOPLODON

  HEADS OF MALE MESOPLODON - All these whales have similar body shape (see page 230) and are distinguished mainly by the jaw and tooth morphology of males. Body coloration is variable in most species.

  SOWERBY’S BEAKED WHALE Mesoplodon bidens 4.5–5.5m, ca. 1000kg

  Tooth erupts from middle of a long strait beak. Large hump in front of blowhole. Body is darker above, lighter below, with limited scarring. Swims alone or in pairs in North Atlantic.

  STEJNEGER’S BEAKED WHALE Mesoplodon stejnegeri

  Broad tooth erupts from peak of the curved lower mandible. Gently sloping head often marked in white (see more on page 230).

  TRUE’S BEAKED WHALE Mesoplodon mirus

  Small tooth erupts from the front of beak. Dark patch around eye (see more on page 230).

  GINKGO-TOOTHED BEAKED WHALE Mesoplodon ginkgodens 4.7–4.9m, ca. 1500kg

  Broad tooth erupts from middle of arched lower jaw. Dark body with little scarring. White spots on belly. Known from a handful of strandings in Pacific.

  GERVAIS’ BEAKED WHALE Mesoplodon europaeus 4.5–5.2m, ca. 1200kg

  Triangular tooth erupts about 10cm from tip of a relatively straight lower jaw. Scarred body is dark above and white below. Rare in Atlantic and Caribbean.

  BLAINVILLE’S BEAKED WHALE Mesoplodon densirostris 4.7m, ca. 1000kg

  Large teeth tilt forward as they emerge from a hump on the lower mandible. Teeth may be covered with barnacles. Has the most curved mouthline of the genus. Dark body is covered with white splotches.

  HECTOR’S BEAKED WHALE Mesoplodon perrini 4.3m, ca. 1500kg

  Triangular teeth located 2cm from tip of straight lower jaw. Gray body darker on back and lighter on belly. Typically found in the southern hemisphere, five strandings have been recorded off southern California.

  HUBBS’ BEAKED WHALE Mesoplodon carlhubbsi 5.3m, ca. 1400kg

  Male has a white cap around blowhole and a massive tooth extending from middle of a flat lower mandible. Strongly arched mouthline caused by raised gum tissue around tooth. Beak usually white. Body of male is dark gray; female is lighter. Found along our western coast.

  PYGMY BEAKED WHALE Mesoplodon peruvianus 3.4–3.7m, weight unknown

  Small, dark-colored whale with a tiny tooth that does not protrude above mouthline. This tropical species is known from only one specimen in North America, although there have been recent sightings off California.

  PLATES 111 AND 112 WHALE AND DOLPHIN DIVE SEQUENCES (not to scale)

  PLATE 113

  CARNIVORE SCATS

  PLATE 114

  VEGETARIAN SCATS

  GLOSSARY

  Annulation A ringlike structure or segment.

  Antitragus A flap on the lower posterior portion of the ear, opposite the tragus.

  Baculum Os penis or penis bone.

  Baubelum Os clitoris or clitoral bone.

  Calcar A spur or spurlike projection from the ankle of a bat.

  Crepuscular Active at dusk and dawn.

  Cusp A pointed or rounded projection on the chewing surface of a tooth.

  Dichotomous Dividing into two parts or classifications.

  Distal Anatomically located farthest from the middle.

  Dorsal On, in, or near the back or upper surface.

  Dorsum The back.

  Ecotone Transitional zone between two ecological communities.

  Facial vibrissae Whiskers, or stiff hairs on the snout or brow of most mammals.

  Fluke Either of the two horizontally flattened halves of the tail of a whale.

  Foramina Openings or orifices, in a bone (singular: foramen).

  Forbs Broad-leaved herbs other than grasses.

  Fulvous Tawny; dull yellow, with a mixture of gray and brown.

  Fuscous Dark brownish gray in color.

  Guard hairs Longer, stiffer hairs that extend beyond the fur.

  Hibernacula The shelters of hibernating animals (singular: hibernaculum).

  Humic Of, relating to, or derived from humus.

  Interfemoral membrane Uropatagium, or tail membrane of a bat.

  Lagomorph Member of the order Lagomorpha, including rabbits, hares, and pikas.

  Malar Relating to the zygomatic bone or the cheek.

  Mammae Milk-producing organ of female mammals; mammary glands.

  Melanistic Darker coloration of the skin, hair, or fur.

  Nose leaf A thin, broad, membranous fold of skin on the nose of many species of bats.

  Papilla(e) A small protuberance on the skin, base of a tooth, or on the top of the tongue.

  Pelage The coat of a mammal, consisting of hair, fur, or wool.

  Pelagic Living in open oceans or seas.

  Pinna(e) The largely cartilaginous projecting portion of the ear.

  Plantar tubercles Knoblike bumps on the soles of the feet.

  Post-mandibular Behind the main bone of the mandibles.

  Post-orbital process Projection on skull, just behind the eye sockets.

  Premolars Teeth between the canines and molars.

  Procumbent To protrude, bend, or lean forward.

  Proximate Anatomically located closest to the middle.

  Riparian Relating to the banks of a natural course of water.

  Rostrum Snout; the long, projecting nose of a mammal.

  Rugose Having many wrinkles or creases; ridged or wrinkled.

  Sagittal crest Raised surface in midline of skull where parietal bones meet.

  Semi-palmated Having the distal portion broad, flat, and lobed.

  Septum A wall separating two cavities as, the nasal septum.

  Sphagnum Mosses of the genus Sphagnum whose decomposed remains form peat.

  Sphenoidal fissure Long narrow opening in the bone situated at the base of the skull.

  Suture The line of junction between two bones, especially of the skull.

  Tail stock Base of the tail of a whale or dolphin.

  Tine A branch of a deer’s antlers.

  Tragus The prominence in front of the external opening of the ear.

  Venter The belly, or underside of the body between the thorax and the pelvis.

  Ventral On or near the belly.

  Unicuspid A tooth having only one cusp.

  Zygoma The jugal, malar, or cheek bone.

  Zygomatic arch Arch formed between the cheekbone and the temple bone.

  INDEX

  The index that appeared in the print version of this title was intentionally removed from the e-Book. Please use the search function on your e-Reading device to search for terms of interest. For your reference, the terms that appear in the print index are listed below.

  Alces alces

  americanus

  Ammospermophilus barristi

  interpres

  leucurus

  nelsoni

  Ammotrapus lervia

  Antelope see Pronghorn

  Antilocapra americana

  Antilope cervicapra

  Antrozous pallidus

  Aoudad see Barbary Sheep

  Aplodontia rufa

  Arborimus albipes

  longicaudus

  pomo

  Arctocephalus townsendi

  Armadillo, Nine-banded Axis axis

  Badger, American Baiomys taylori

  Balaena mysticetus

  Balaenoptera acuto rostrata

  borealis

  edeni

  musculus

  physalus

  Bassariscus astutus

  Bat see also Myotis and Pipistrelle Allen’s Big-eared Big Brown Big Free-tailed Californian Leaf-nosed Eastern
Red Evening Florida Bonneted Greater Bonneted Greater Mastiff see Greater Bonneted Bat Hairy-legged Vampire Hoary Lesser Long-nosed Mexican Free-tailed Mexican Long-nosed Mexican Long-tongued Northern Yellow Pallas’s Mastiff Pallid Peters’s Ghost-faced Pocketed Free-tailed Rafinesque’s Big-eared Seminole Silver-haired Southern Yellow Spotted Townsend’s Big-eared Underwood’s Bonneted Underwood’s Mastiff see Underwood’s Bonneted Bat

  Vampire see Hairy-legged

  Vampire Bat

  Velvety Free-tailed see Pallas’s Mastiff Bat Western Red Western Yellow Bear, Black Brown Glacier see Black Bear

  Grizzly see Brown Bear

  Kermode see Black Bear

  Kodiak see Brown Bear

  Polar Beaver, American, Mountain see Sewellel Beluga, Berardius bairdii

  Bison bison

  Bison, American Plains see American Bison

  Wood see American Bison

  Blackbuck Blarina brevicauda