Savannah/Bosc Wild Stomach Content

Discussion in 'Monitors & Tegus' started by SavBoy, May 25, 2011.

  1. SavBoy

    SavBoy Embryo

    Messages:
    4
    From lososandgreen.pdf I found. MR= prey/predator mass ratio

    "Varanus exanthematicus: Sub-saharan Africa, open habitats. Total length c. 2m (Mertens, 1942c). Savanna monitors reportedly wait near flowers in trees to eat birds, capturing them with a sweep of the tail (Rose, 1962). One from South Africa contained 2 juvenile tortoises and a grasshopper (de Waal, 1978). Beetles, millipedes, caterpillars and orthopterans (grasshoppers, crickets, locust) were the most important items in 24 stomaches from Senegal; three had eaten lizard eggs, including one that contained 11 V. exanthematicus eggs. Other prey were snails, centipedes, a hymenopteran (sawflies, bees, wasp, ants) and a scorpion. The lizards tended to eat many items (1-105/stomach mean =35.3), and many of a particular type. For lizards that had eaten a particular prey, the mean number of millipedes was 29.1, of beetles 10.0, of orthopterans 9.4 and of lizard eggs 10.7 (Cisse, 1972). Insect predominated in ten specimens we examined. More than half had eaten beetles, and they were the only type eaten by more than two individuals. Snails and lepidopteran (moths, butterflies) larva were also important items by number. The only vertebrates were eaten by small monitors; a 42.4g V. exanthimaticus ate a 7.4g ranid frog (MR = 0.1745) and a 147g specimen took a 13.4g Bufo sp.(toad) (MR = 0.0912). All large specimens contained only relatively small invertebrates. One 1.31 kg specimens contained 35 lepidopteran larva, ranging from 0.7g to 3.0g (MR = 0.0005 - 0.002). The range in items per stomach was great; two individuals had more than 30 items and three other specimens contained four or more items.

    CISSE,M. Bulletin de L'insitute Fondamental d'Afrique Noire. 1972 34 (2): 503-515. The diet of Varanids in Senegal. Translated by Daniel Bennett
    on page 21. Its translated to english. Copied and pasted from another post.

    "In total we analysed the stomach contents of 28 animals. The results are presented by monitor and by month in table I. The identified prey was made up exclusively of invertebrates except for the eggs of Agama agama and V. exanthematicus. The following were found;

    1. Insects.
    a. Coleopera:
    - Carabids: Ctenosta senegalense, Megacephala megacephela, Scarites sp.......................... ( Ground beetles)
    - Curculionids: Episus sp......................................... ( Weevles)
    - Dytiscids: Cybister sp............................................ ( Water beetles)
    - Meloids: Psalydolytta fusca.................................. ( Blister beetles)
    - Scaribids: Adoretus sp. Anomala sp. Oryctes sp. Schizonycha africana ............................ (Scarab Beetles)
    - Tenebrionids: Pimelia senegalensis, Phrynocolus dentatus, Vieta senegalensis............................. (Darkling Beetles)
    b. Dictyoptera: Mantes: Epitenodera gambiensis.......................................... ( Mantids)
    c. Hymenoptera: Aphids: Xylocopa sp............................................. ( Carpenter bees )
    d. Lepidotera: chiefly Chenilles and Sphingids................................ ( Moths)
    e. Orthoptera:
    - Acridids: Acanthacris ruficornis citrina, Anacridium sp., Kraussaria angulifera, Cataloipus sp.,
    Oedaleus nigeriensis, Humbe tenuicornis.............................................. ( Locusts)
    - Gryllids: Gryllus bimaculatus................................ (Field Crickets)
    - Pyrgomorphids: Zonocerus variegatus................................... ( Grasshopper)
    - Tettigonids: Homorocoryphus nitidulus vicinus.................................... ( African Bush Cricket)
    2. Arachnids: a scorpion of the family Buthidae.
    3. Myriapods: Diplopodes (Iules) and Chilipods (Scolopendra)................................... (Millipedes and Centipedes)
    4. Molluscs: Gasteropods pulmones Helicarionines....................................... (Snails)
    5. The eggs of Varanus exanthematicus and Agama agama

    In order of number, prey was distributed as follows;
    Myriapods 48.32%
    Insects 45.49% of which 21.22% were Coleopterids, 15.21% Lepidoterans (Chenilles) and 8.84% Orthopterans.
    Eggs of Agama and V. exanthematicus 3.75%.
    Gasteropod molluscs 2.35%.
    Arachnid scorpions 0.11%.

    These results interpret the respective percentages of prey items, but they do not give information on their distribution in the predators. This we have indicated by the degrees of prescence (LESCURE). The number of animals containing each prey is given. In other words, it shows the percentage of animals containing each prey. Table II shows the different prey with their percentages and frequency of prescence. The prey most frequently consumed by V. exanthematicus in the area where our research was based was the Coleopterids (64.28%), the Myriapods (53.57%), larvae of Lepidopterans (46.42%) and the Orthopterans (35.71%). If we consider this diet by month we need to establish whether it reflects the availability of the large invertebrates of that period. In fact, the Coleopterans, larvae of Sphingides and the Myriopods, which are abundant during the first half of the winter constitute the main items of prey during this season, whilst they are absent from the intestines towards the end of the season, replaced at that time by the Orthopterans which become more numerous. Otherwise, except for the reptile eggs (Agama and Varanus) we did not find any trace of vertebrates in the diet of V.exanthematicus. This species feeds exclusively on invertebrates and eggs (including those of its own species). Towards the end of December all feeding ceases until favourable conditions return. Is this diet different from that of Varanus nilocticus? This is what we are going to find by examining the stomach contents of the second species."




    Copy and pasted from the other forum. Just posting some of the scientific info I've found on savs diet. I read a very long debate on this regarding the small population used, seasonal changes, range of savs, if a sav would eat a rodent in the wild, ect, ect, ect. Mostly just posting it for info.

    Note for mods: I got links to other things but they are all pdfs. Can/should I post links? They are scientific papers regarding experiments not forum posts.
     
  2. JEFFREH

    JEFFREH Administrator

    Messages:
    5,483
     
  3. StikyPaws312

    StikyPaws312 Moderator

    Messages:
    3,899
    Wow, I don't own a sav but it's always extremely helpful to the general herp keeping population to find out exactly what the wild is doing to survive. I wonder if the article had information on exactly where each monitor was found and what was in each one's stomach. I have read similar studies on Leachies (New Caledonia and surrounding islands) that have really helped bring the captive care to the most ideal for the Leachies as well as shedding light on similar species.

    I'm sure that the articles would help, and although you can't actually post the PDF's themselves I'm sure that the links would be beneficial to people who have Savs. Also if you only post a link it doesn't infringe upon any copyright laws. Thank you for all the information!
     

Share This Page