Reptile Introduction and Wildlife Identification Assignment

Module 2: Wildlife Identification Assignment

  • Assignment 1: Wildlife Identification

    • Task: Identify specific wildlife species.

    • Species Selection: Students must choose one species from each of four provided lists:

      • Mammals

      • Birds

      • Reptiles

      • Amphibians

    • Reason for Lists: Lists were created because past students chose species difficult to find information on.

    • Format: Create a PowerPoint presentation (or use Microsoft Word, or any preferred tool, but PowerPoint is ideal if proficient).

    • Content Example (from previous student work):

      • Wildlife ID on a specific species (e.g., Western Tanager, Bull Snake).

      • Methods to identify the species (e.g., evidence, environment, habitat, physical characteristics).

      • Examples shown: pine forest context for a cow elk, feather evidence for a flicker, bull snake environment.

    • Instructions: Currently available instructions on CCT will be updated to be clearer.

    • Deadline Change: The original deadline of September 2828th has been moved to next Wednesday (specific date not given, but implied to be October 44th or 1111th, depending on the week this was given), due to the module being initially unavailable.

    • Important Note: If a new module is announced and not visible, students must alert the instructor immediately.

Introduction to Reptiles

  • General: Reptiles are found in diverse global locations.

  • Personal Experience: Instructor will show many snakes; asks about fear of snakes and ownership of reptiles.

Taxonomy of Reptiles (Reptilia)

  • Three Main Orders:

    1. Testudinata: Turtles and Tortoises (known distinction exists).

    2. Squamata: Snakes and Lizards (share similar characteristics within this order).

    3. Crocodilia: Crocodiles, Alligators, Caimans, and Gharials (fewer species, possibly more ancient).

  • Unique Order:

    • Rhynchocephalia: Contains only one species, the Tuatara (SphenodonpunctatusSphenodon punctatus).

  • Examples of Notable Squamata:

    • Gila Monster: Associated with Ozempic (likely a previous lecture connection or analogy).

    • Komodo Dragon: Very large, saliva contains bacteria causing severe, potentially fatal infections (not poison).

Characteristics of a Reptile

  • Skin: Covered with scales; can be shed (molting process involves twisting and turning, takes time to regrow venom).

  • Limbs: Paired limbs designed for crawling; some species are legless (e.g., snakes).

  • Heart Structure:

    • Typically a three-chambered heart with two atria and one ventricle (allowing for some blood mixing).

    • Crocodilians are an exception, possessing a four-chambered heart (similar to birds and mammals).

  • Thermoregulation: Ectothermic (poikilothermic), meaning their body temperature fluctuates with ambient temperature. They are not warm-blooded like homothermous birds (e.g., ducks on ice warm one leg at a time by bringing it close to their body).

  • Toxins: Some reptiles produce toxins; they are venomous, not poisonous. "Poisonous" typically refers to toxins ingested or absorbed, while "venomous" refers to toxins injected (e.g., through a bite).

    • Venom Glands: Possess a venom gland and compressor muscle for injection.

    • Anti-venom Production: Venom can be extracted for use in creating anti-venom.

    • Venom Replenishment: Venom production is not instantaneous; it requires several days to replenish after a significant discharge.

Locomotion

  • Alligators: Walk with a more open or spread-out stance.

  • Snakes: Exhibit two distinct types of movement:

    • Concertina

    • Serpentine

    • Sidewinding

    • They also swim using similar undulating movements.

Circulatory System (Revisited)

  • Amphibians: Discussed in a previous lecture, known for a less efficient circulatory system.

  • Reptiles (e.g., Turtles): Exhibit mixed blood circulation due to the three-chambered heart (less efficient than four-chambered).

  • Birds and Mammals: Possess a four-chambered heart which completely separates oxygenated and deoxygenated blood, indicating a more efficient system.

Reptile Reproduction

  • Fertilization: Internal fertilization (unlike amphibians which often have external fertilization).

  • Mating Rituals: Males often defend territories and engage in fights (e.g., intertwining snakes are often males fighting, not mating).

  • Eggs: Produce an amniotic egg with a soft shell.

  • Modes of Birth:

    • Oviparous: Lay eggs externally (e.g., most turtles, tortoises, crocodiles, alligators, caimans, gharials). Nests may or may not receive parental care. Sea turtles can lay hundreds of eggs.

    • Viviparous: Give live birth internally, with no egg stage (similar to mammals). Some lizards and snakes exhibit this.

    • Ovoviviparous: Eggs are developed and hatched internally, then live young are born (some lizards and snakes).

  • Temperature-Dependent Sex Determination (TSD):

    • Significance: Nest temperature plays a crucial role in determining the sex of hatched offspring (e.g., turtles).

    • Impact of Climate Change: Warmer temperatures can lead to an all-female clutch, while colder temperatures can result in an all-male clutch. This imbalance directly threatens population stability by reducing breeding opportunities.

Threats to Reptile Populations

  • 1. Habitat Destruction:

    • Loss and fragmentation of natural environments.

  • 2. Pollution:

    • General: Similar issues to amphibians.

    • Plastic/Microplastic Pollution: Poses a significant threat, especially to sea turtles.

      • Straws: The viral image of a turtle with a straw in its nose led to bans on plastic straws, despite being a single documented case. However, the larger problem concerns plastic bags mistaken for food.

      • "Floater Syndrome": Turtles ingest plastic, making them buoyant and unable to dive effectively, leading to starvation, increased predation risk, and collisions with boats.

      • Beach Debris: Microplastics in dunes on nesting beaches (e.g., Florida loggerhead sites) retain heat, exacerbating TSD issues by skewing sex ratios towards females.

      • Solutions: UN campaigns, local beach cleanups, ocean cleanup initiatives.

  • 3. Invasive Species:

    • Cats: Domestic cats are significant predators of wildlife.

    • Small Indian Mongoose: Introduced species that prey on native reptiles.

    • Brown Tree Snake: Introduced to Guam, causing immense damage to local species, including other snakes (snakes can eat other snakes).

  • 4. Road Mortality/Vehicle Collisions:

    • Periods of High Risk: Occur during rain events (e.g., April, July) when reptiles disperse, and during autumn (September-October) as they move to overwintering sites.

    • Survival: Some injured animals can survive and may be rehabilitated if brought to shelters.

  • 5. Illegal Collections/Exotic Pet Trade:

    • Despite regulations, reptiles are illegally collected and traded (e.g., anecdote of a professor smuggling two small, illegal snakes).

    • Animals are often hidden in luggage compartments.

    • Often sold on black markets.

  • 6. Climate Change:

    • Sea Level Rise: Threatens coastal habitats, vulnerable marshes, and contributes to increased flooding.

    • Increased Storm Intensity: Hurricanes and other severe weather events cause widespread habitat damage, desiccation, and erosion.

    • Temperature Changes: As mentioned, warmer temperatures impact sex determination, leading to skewed sex ratios and potential population decline.

    • Community-Level Impacts: Affects different life stages (eggs, tadpoles, adults) and entire communities.

Crocodilians (Focus Area)

  • General Characteristics of Crocodilians:

    • Flattened snouts.

    • Long, powerful jaws (primarily for closing, not opening).

    • Excellent swimmers and surprisingly fast runners.

    • Mating rituals often involve low-wavelength sounds that cause water vibrations and jaw-slapping on the water surface.

  • 1. Crocodiles:

    • Size: Can reach 12−1812-18 feet in length.

    • Habitat: Primarily tropical, found in brackish or saltwater (e.g., tip of Florida). Possess salt glands to tolerate saline environments.

    • Teeth: Both upper and lower jaw teeth are visible when their mouth is closed.

    • Hunting: Ambush predators, waiting for prey to come near (e.g., wildebeest crossings, eating once a year).

    • Parental Care: Some species exhibit parental care for their nests.

  • 2. Gharials:

    • Snout: Distinctive, very narrow snouts.

    • Habitat: Found in freshwater environments (sand banks, deep pools).

    • Size: Large, but not as massive as some crocodiles.

    • Diet: Primarily fish; sit and wait predators.

  • 3. Alligators:

    • Habitat: Mostly freshwater (slow-moving rivers, swamps, marshes, lakes). Can tolerate brackish water for short periods but lack salt glands for prolonged exposure.

    • Weight: Large individuals can weigh up to 11 ton.

    • Walking Posture: Walk with their bodies held higher off the ground compared to crocodiles.

    • Snout: Broad, U-shaped snouts.

    • Teeth: Only upper teeth are visible when their mouth is closed.

    • Diet: Opportunistic feeders; will eat anything that moves, including small alligators.

  • 4. Caimans:

    • Species: Six known species, generally smaller and considered "cuter."

    • Habitat: Primarily freshwater, with limited tolerance for brackish water due to lacking salt glands.

    • Diet: Hemet diet (diverse diet comparable to alligators) - eat anything that moves, including insects (especially beetles) and small animals like rats.

    • Behavior: Borrowers, creating small caves. Exhibit territorial defense (head bobbing, mouth gapping, chasing intruders).

    • Male Displays: Males display crests and engage in ritualistic "play."

    • Reproduction/Lifespan: Reach sexual maturity between 10−2010-20 years old and can live up to 6060 years, requiring long-term commitment as pets.

    • Conservation Status: Some species (e.g., Black Caimans, Chinese Alligators) are endangered or critically endangered.