I.

Marine Reptiles

C.

• • • • • Sea Snakes 65 species – Mainly tropical (Indian, Pacific) • Coral reefs, open ocean • • • • • • • • • • • Adaptations to aquatic lifestyle Scales reduced or absent Nostrils higher on head vs. terrestrial snakes; specialized valves that seal nostrils when submerged • Bodies flattened laterally (3-4 feet long at maturity) Paddle-shaped tail video • Huge lung (extends into tail); gas exchange across trachea & skin Can dive to 150 m (typically ~5 m); hold breath 2+ hours Eliminate salt via salt gland under tongue Ovoviviparous Gestation 4-11 months Few species lay eggs on shore Venomous Closely related to cobras Venom typically used to kill small prey (fishes, squids) May hunt in schools Some actively trap prey; others lie in wait Few natural predators (seabirds, sharks, saltwater crocodiles)

I.

Marine Reptiles

D.

• • • • •

Saltwater Crocodile

• • • • • • • Four-chambered heart (similar to birds) One species – E Indian Ocean, W Pacific, Australia Mostly inhabit mangrove forests • Largest crocodile species - Males larger than females May reach 23+ feet and 1000+ kg Diverse diet Fishes, crustaceans, snakes, birds, mammals, fishes Drink seawater Salt glands on tongues  excess salt Slow to reach sexual maturity Males mature at 15-16 years; females at 10-12 years • Eggs (usually 40-60; up to 90+) laid in mounds of mud/debris Guarded by female • • Environmental sex determination Mostly males ~31.6 o C Warmer or cooler: More females

II.

• • • • • • •

Seabirds

• • • • • • • • • • • About 250 species Spend a significant part of life at sea Feed on marine organisms Webbed feet for swimming Endotherms and homeotherms Gannet Allows seabirds to live in a wide variety of conditions Need considerable food to maintain body temperature in cold regions Four-chambered heart; efficient circulatory system Feathers (modified reptile scales) help conserve body heat Trapped air provides insulation and buoyancy Gland above base of tail produces oil that birds add to feathers with preening Flight (facilitates feeding, predator avoidance, expanded range and habitat use) Reduced body weight (hollow bones, no teeth, reduced gonads during non-breeding season, no urinary bladder) Relatively large brain, good color vision Salt consumption  salt glands above eyes Nest on land Often colonial Frequently mate for life

Fig. 11-11

II.

Seabirds

A.

• • •

Shorebirds (Waders)

Forage/Feed in intertidal zone Adapted for walking on shores

• •

Most feed on infaunal invertebrates

Many with sensitive nerve endings at ends of bills to aid in prey detection Resource partitioning via diverse bill lengths Video

Curlew Sanderling Willet Sandpiper

Plover Avocet II.

Seabirds

A.

• 1.

2.

Shorebirds (Waders)

• • Often ground-nesting

Oystercatcher Fig. 11-12

Oystercatchers Thick bill: open bivalves, pry limpets off rocks, crush crabs, probe for crustaceans & worms video video

Sandpiper

Plovers and Turnstones video Short bill; eat small animals collected near surface 3.

4.

5.

• • Sandpipers and Curlews Sandpipers: short bill; feed on small prey when water recedes Curlews: long, curved bill; feed on deep-living crustaceans video • Avocets and Stilts Long legs, bills; probe sediments for prey video • • Herons (incl. egrets, bitterns) Long bill; stand and wait predator video Feed on small fishes, crustaceans

Egret

Skua Skimmer II.

Seabirds

B.

• 1.

2.

3.

4.

Gulls and Relatives

Lesser black-backed gulls

Global distribution, not always near ocean

Fig. 11-17

• • • Gulls Highly adaptable; wide distribution Dietary generalists; creative feeding behaviors video Nest in colonies; can produce several clutches each year • • Terns Plunge to catch near-surface prey video Nest in colonies, often very large

Arctic tern

• • Skuas and Jaegers Aggressive predators (skuas), food thieves (jaegers) video Ecological equivalent to raptors (skuas) • • Skimmers/Scissorbills Asymmetrical bills (lower longer) video Skim water surface to attract prey; fly opposite direction to feed

Herring gull Black skimmer Common tern Pomarine jaeger

II.

Seabirds

Parakeet auklet

B.

• 5.

Gulls and Relatives

Global distribution, not always near ocean

Atlantic puffin

• • • Alcids (auks, puffins, murres) Countershaded; resemble penguins (convergent evolution) “Fly” through water, pursuing prey (fishes, squids, shrimps) video Nest on ledges and among boulders (auks, murres) or on cliffs (puffins); single pear-shaped egg guarded by both parents

Common murre

Fig. 11-21

Brown pelican Fig. 11-24 II.

Seabirds

Red-footed booby Frigatebird

C.

• • 1.

2.

3.

4.

Pelicans and Relatives (Pelecaniformes)

Webs between all four toes Mostly coastal, tropical and warm temperate • • Pelicans Subsurface feeding with gular pouch • Dive to capture prey below surface video video Use subcutaneous air sacs to return to surface • • • Boobies Unusual courtship behavior video Resource partitioning: foraging ranges (blue-footed – nearshore, masked – intermediate, red-footed offshore) Dive (up to 30 m!) to capture prey below surface video • • Cormorants Swim on surface; dive (to 40+ m!) to catch prey video Lack oil glands; must dry after swimming • • Frigatebirds Impressive courtship displays video Skim surface for prey; may steal fish

Cormorant