Favoritos de zoefoster

One of the most amazing worms I've ever seen. About 8 mm long, climbed out of a clump of tunicates we put in a dish, undoubtedly sponges and other things mixed in too. Very close resemblence to this image, ID'd as A. speciosa at http://invasions.si.edu/nemesis/calnemo/GroupSummary.jsp?GRP=Annelids-Polychaetes, but given the image at http://biodiversitylibrary.org/page/34212266 that seems like it might be wrong.

Flushed from tree hole on the side of the causeway. Funny place to find this species, as there are no trees over 25ft on the causeway. G. sabrinus ruled out by lack of cone bearing trees in the vicinity, and by tail width (as well as the tail width taper). Another individual was discovered in the tree hole as well.

Chipmunks in southeastern Canada and northeastern United States are commonly known as the eastern chipmunk, scientifically named Tamias striatus (T. striatus) 1. A defining feature of this species is the two-paired innermost dorsal stripes being twice as wide as the other three stripes on the body1. Their diet, habitat, behaviour, and susceptibility to predators, vary depending on the season. For example, during mating season, males become more social to find a female to copulate with. However, did you know females also have a mechanism to attract mates? The following report will explore the varying aspects of the T. striatus such as, its physical characteristics, habitat, diet, reproductive behavior, and susceptibility to predators.
T. striatus are scattered over a wide geographic range, varying in size and weight. The average adult size for the eastern chipmunk is 225 to 268 mm, with the tail being an average of 72 to 101 mm in length, while a newborn is about 66 mm in length1. The average adult weighs from less than 80 to 125 grams, but a newborn weighs about 2.5 to 5 grams1. Their lifespan depends on their birth season, with chipmunks born in the spring having a higher survivorship than those born in the late summer1. Although survivorship varies among individuals, the average lifespan of these chipmunks is 30 months in the wild, and they can live up to eight years under captivity2.
The eastern chipmunk is found in many parts of Canada and the United States. In the Gulf States of the United States, they reside in the parishes by the Mississippi River and are present in the northwest area of Florida1. In Canada, they geographically range from Lake Manitoba eastward to the Quebec coastline north of Anticosti Island1. Eastern deciduous forests1 and sparse understory woodlands, with herbaceous growth and trees are their preferred habitats3. They prefer uncrowded areas that have objects (logs, trees, etc.) 4 that provide them with elevation to spot predators. They also reside in man-made habitats such as clear-cut forests, farmland woodlots, and residential areas4. In these habitats, T. striatus create burrow systems ranging from 0.11 to 1.38 acres, with a depth of less than 1 meter depending on the season1. During late summer and fall, chipmunks are the most active as they gather food for hibernation in the winter, and must increase their burrow system to accommodate for the food5.
These chipmunks use pouches in their cheeks to gather primary foods such as, seeds, nuts, and acorns to store for hibernation1. During the spring and autumn, their diet mainly consists of plant material, but in late spring and summer there is an increase in the consumption of invertebrates, insects, fungi, and small mammals6. It is suggested that there is an increased rate of consumption of non-plant-based material because it is high in protein, which is an important nutrient for newborn chipmunks6. Eastern chipmunks also prefer a diet consisting of cherries, wild lily, nannyberries, and strawberries in late July5. Therefore, due to the variation in their diet they are considered omnivores. They have an average calorie count of about 32.7 to 35.7 kcal per day1.
The social organization of the T. striatus is territorial and solitary because they are dominant over their own burrows3. Although these chipmunks are independent during the annual cycle, they become very active during mating season. Male chipmunks gather around female burrows to chase and isolate the female for copulation when she emerges from her burrow3. The adult males are very aggressive during the mating bout and squeal in a high pitch manner to drive rivals away3. Unfortunately, if a more dominant adult male spends too much time chasing away juvenile males, he risks his chance to copulate as another male could take the female away. The mating bouts usually last until mid-afternoon, and female chipmunks are capable of copulating with multiple males3. Eastern chipmunks are unique because they have two breeding seasons each year, one during March to April and another in June to July7. The females are able to participate in either one or both breeding seasons1.
It is common in many species, including the T. striatus, for males to compete with other males to attract a female. However, did you know that these females also have a mechanism to attract males? Females leave an olfactory cue (anal or vaginal secretions) around their burrow to attract males3. The anus of female T. striatus has anal glands and glandular tissue that secrete hormones and reproductive pheromones to attract the males to her nest8. The reproductive pheromones released are so strong that even after copulation, some males still wander around the entrance of the female burrow1.
While chipmunks are foraging or away from their burrows during mating season, they have a high risk of becoming prey to snakes, hawks, weasels, foxes, large frogs, and bobcats1. T. striatus warn and communicate with each other using four different alarm calls: a single high-pitched “chip”, a chip-trill, a series of chips, and a repeated low-pitched “cuk”1. The chip-trill call is typically used during an escape rush1.
Due to its large population, the T. striatus is listed as one of the least concerned species under the International Union for Conservation of Nature Red List9. Furthermore, because of the flexibility in their habit choice, they have increased survival. Using burrows, hoarding food, and hibernating during unfavorable environmental conditions also make them less susceptible to extinction9.
In conclusion, T. striatus is a well-known species easily found in the southeastern and northeastern parts of Canada and the United States respectively, and their choice in habitat, diet, and behaviour are fundamental to their fitness and survival.

References (CSE – citation sequence style)

1. Snyder DP. Tamias striatus. Mamm Species [Internet]. 1982 [cited 19 Oct 2016];168(1): 1-8. Available from: http://www.jstor.org.libaccess.lib.mcmaster.ca/stable/pdf/3503819.pdf
2. Montiglio PO, Garant D, Bergeron P, Messier GD, Reale D. Pulsed resources and the coupling between life-history strategies and exploration patterns in eastern chipmunks (Tamias striatus). J Anim Ecol [Internet]. 2014 [cited 19 Oct 2016]; 83(1): 720-728. Available from: http://onlinelibrary.wiley.com.libaccess.lib.mcmaster.ca/doi/10.1111/1365 2656.12174/epdf
3. Yahner RH. The adaptive nature of the social system and behaviour in the eastern chipmunk, Tamias striatus. Behav Ecol Sociobiol [Internet]. 1978 [cited 19 Oct 2016]; 3(1): 397-427. Avalable from: http://link.springer.com.libaccess.lib.mcmaster.ca/article/10.1007/BF00303202
4. Mahan CG, Yahner RH. Effects of forest fragmentation on burrow-site selection by the eastern chipmunk (Tamias striatus). Am Midl Nat [Internet]. 1996 [cited 19 Oct2016]; 136(2): 352-357. Available from: http://www.jstor.org.libaccess.lib.mcmaster.ca/stable/pdf/2426739.pdf
5. Forsyth DJ, Smith DA. Temporal variability in home ranges of eastern chipmunks (Tamias striatus) in a southeastern Ontario woodlot. Am Midl Nat [Internet]. 1973 [cited 19 Oct 2016]; 90(1): 107-117. Available from: http://www.jstor.org.libaccess.lib.mcmaster.ca/stable/pdf/2424271.pdf
6. Wrazen JA, Svendsen GE. Feeding ecology of a population of eastern chipmunks (Tamias striatus) in southeast Ohio. Am Midl Nat [Internet]. 1978 [cited 19 Oct2016]; 100(1): 190-201. Available from: http://www.jstor.org.libaccess.lib.mcmaster.ca/stable/pdf/2424789.pdf
7. Smith LC, Smith DA. Reproductive biology, breeding seasons, and growth of eastern chipmunks, Tamias striatus (Rodentia: Sciuridae) in Canada. Can J Zool [Internet]. 1971 [cited 19 Oct 2016]; 50: 1069-1085. Available from: http://www.nrcresearchpress.com.libaccess.lib.mcmaster.ca/doi/pdf/10.1139/z72145
8. Yahner RH, Allen BL, Peterson WJ. Dorsal and anal glands in the eastern chipmunk, Tamias striatus. Ohio J Sci [Internet]. 1979 [cited 19 Oct 2016]; 79(1): 40-43.Available from: https://kb.osu.edu/dspace/bitstream/handle/1811/22593/V079N1_040.pdf?sequece=1
9. Liow LS, Fortelius M, Lintulaakso K, Mannila H, Stenseth NC. Am Nat [Internet]. 2009 [cited 19 Oct 2016]; 173(2): 264-272. Available from: http://www.jstor.org.libaccess.lib.mcmaster.ca/stable/pdf/10.1086/595756.pdf