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BC Conservation Data Centre: Species Summary


Hemphillia dromedarius
Dromedary Jumping-slug

 
Scientific Name: Hemphillia dromedarius Branson, 1972
Scientific Name Synonyms: Hemphillia malonei
English Name: Dromedary Jumping-slug
 
Classification / Taxonomy
Scientific Name - Concept Reference: Turgeon, D. D., J. F. Quinn, Jr., A. E. Bogan, E. V. Coan, F. G. Hochberg, W. G. Lyons, P. M. Mikkelsen, R. J. Neves, C. F. E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F. G. Thompson, M. Vecchione, and J. D. Williams. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. 2nd Edition. American Fisheries Society Special Publication 26, Bethesda, Maryland. 526 pp.
Classification Level: Species
Species Group: Invertebrate Animal
Species Code: MO-HEMDRO
Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Stylommatophora Arionidae
   
Conservation Status / Legal Designation
Global Status: G3G4 (Aug 2005)
Provincial Status: S2 (Feb 2024)
BC List: Red
Provincial FRPA list:   
Provincial Wildlife Act:
COSEWIC Status: Threatened (May 2014)
SARA Schedule: 1  -  Threatened (Jan 2005)
General Status Canada:
   
Ecology & Life History
General Description: External morphology provided in Branson (1972). Anatomy figured in Ovaska et al. (2002). Relatively large slug with visceral puch elevated into a pronounced hump and a part of the internal shell plate visible through a slit in the mantle. Tail laterally compressed, keeled, and tipped with a horn0like protuberance, termed the caudal horn. The predominant color of the mantle and foot is typically gray with cream-colored mottling on the sides; the sole of the foot is pale yellow, orange-yellow, or cream colored (COSEWIC, 2003).
Subspecies Comments: There are no recognized subspecies.
Identification Comments: A large slug, length up to about 60 mm when extended in movement, with a distinctive appearance (Forsyth 2004). The visceral pouch is raised into a pronounced hump, and the yellowish internal shell plate is partially visible through a slit in the mantle. The overall dorsal colouration ranges from grey to tan and brown. The underside (sole of the foot) is pale yellow, orange, or grey.
Global Reproduction Comments: Hemphillia dromedarius is a simultaneous hermaphrodite and lays eggs. Branson (1972) reported a clutch size of 5060 eggs for Washington populations. The oval, semi-opaque eggs measured ca. 3.3 mm in length and 2.5 mm in diameter. Oviposition took place in wet or moist decaying wood. Nothing is known of the reproductive biology of the species in British Columbia (COSEWIC, 2003).
Provincial Reproduction Comments: This species is oviparous and hermaphroditic (each individual possessing both male and female reproductive organs). Details of reproductive biology are unknown. No eggs or juveniles have been found in BC.
Provincial Ecology Comments: The species exists at the northern limits of its distribution on Vancouver Island. Populations at the limits of a species' range may become important for the survival of the species under large-scale perturbations, such as climate change. Its habitat use appears to be more restricted here than farther south in the United States, where it is found in a variety moist forest types and in subalpine talus (Ovaska et al. 2002).
Migration Characteristics:
(Global / Provincial)		 
    Nonmigrant:
    Local Migrant:
    Distant Migrant:
    Within Borders Migrant: 		N / Y
N / N
N / N
na / N
Provincial Mobility & Migration Comments: This species is thought to have low mobility and dispersal ability, similar to many other terrestrial gastropods (NatureServe 2007). Passive dispersal with the movement of water, wind, or other elements or by animal vectors is unlikely. Inadvertent transport by humans is also unlikely.
Habitats:
(Type / Subtype / Dependence) 		Forest / Conifer Forest - Moist/wet / Obligate
Global Habitat Comments: Habitat requirements of H. dromedarius are poorly known. In Washington, the species has been reported from elevations of 238 m (780 feet) to 1436 m (4710 feet; Branson 1972); most reported localities are from elevations above 700 m. The Washington localities are in mature and old-growth forest, but at several high-elevation sites on the east slope of the Cascade Mountains the slugs occur on talus substrates in sparsely wooded, subalpine habitats (Ovaska et al. 2002). It is unknown whether the species uses earlier seral stages within logged landscapes, and its habitat relationships have not been examined.
The Washington localities are in mature and old-growth forest, but at several high-elevation sites on the east slope of the Cascade Mountains the slugs occur on talus substrates in sparsely wooded, subalpine habitats (Ovaska et al. 2002). It is unknown whether the species uses earlier seral stages within logged landscapes, and its habitat relationships have not been examined.
The Washington localities are in mature and old-growth forest, but at several high-elevation sites on the east slope of the Cascade Mountains the slugs occur on talus substrates in sparsely wooded, subalpine habitats (Ovaska et al. 2002). It is unknown whether the species uses earlier seral stages within logged landscapes, and its habitat relationships have not been examined. On Vancouver Island, the elevation of the 6 known localities ranges from near sea-level to ca. 1060 m. The three low elevation localities are on the wet, west coast of the island; the remaining 3 localities are from elevations >700 m in the southern interior of the island. Five of the localities are in remnant patches of old-growth, coniferous forest dominated by Western Hemlock (Tsuga heterophylla) and Western Redcedar (Thuja plicata; Fig. 5). The remaining site (in the outskirts of the village of Bamfield on the west coast of the island) is in a selectively logged forest. This site contains attributes of older forests, including some large trees and abundant coarse woody debris. The forest floor at all the sites is composed of thin, compact, needle litter, and most sites contain abundant coarse woody debris, including large-diameter pieces (COSEWIC, 2003).
Provincial Habitat Comments: In B.C., this species is associated with older, coniferous forest and old-growth forest attributes, such as abundant coarse woody debris and layered, complex forest floor structure (COSEWIC 2003a; ECCC 2017). Important microhabitat features consist of abundant coarse woody debris, including large-diameter decaying logs, and shaded, moist forest floor conditions. Eggs are probably laid in moist microhabitats, such as within large decaying logs, as reported for the species in the United States. All known sites in the interior and eastern Vancouver Island are at high elevations, whereas sites on the wetter west coast of the island are at low elevations (COSEWIC 2003a, 2014d; Ovaska and Sopuck 2004d, 2006a,b; ECCC 2017). Higher elevation sites in drier landscapes probably provide required moist conditions throughout much of the growing season.
Food Habits: Herbivore: Adult
Global Food Habits Comments: The diet of H. dromedarius is unknown. In captivity, the species feeds sparingly on fresh vegetable matter; in contrast H. malonei and H. glandulosa readily consume these foods (KO, pers. obs.). Under natural conditions, the species may be a fungivoredetrivore. The availability of food as a limiting factor is unlikely, unless the species requires specialized food items (such as particular species of fungi or lichens) that are only present in certain forest types or ages (COSEWIC, 2003).
Provincial Food Habits Comments: The species is herbivorous-fungivorous, but little specific information is available on its food habits (COSEWIC 2003a). On Vancouver Island, the slugs have been observed feeding on a variety of mushrooms on several occasions (Ovaska and Sopuck 2003c, 2004, 2006a).
Global Phenology:
Provincial Phenology:
(1st half of month/
2nd half of month)		 Jan: Present / Present
Feb: Present / Present
Mar: Present / Present
Apr: Active /
May: Active / Active
June: Active / Active
July: Active / Active
Aug: Active / Active
Sept: Active / Active
Oct: Active / Active
Nov: Active / Active
Dec: Present / Present
Provincial Phenology Comments: Individual slugs live for more than one year, but details of the life-cycle are unknown. On Vancouver Island, adult-sized slugs have been found in all months from April to November (COSEWIC 2003a, Ovaska and Sopuck 2003c, 2004, 2006a,b). The length of the activity period is likely to vary according to elevation and site-specific conditions. The slugs probably estivate during dry periods in the summer but can become active after heavy rain fall events. Eggs are probably laid in the autumn and hatch the following spring, but no information is available.
Colonial Breeder: N
Length(cm)/width(cm)/Weight(g): 6/ /
Elevation (m) (min / max): Global: 
Provincial:  20 / 1250
   
 
Distribution
Endemic: N
Global Range Comment: Known from western Washington (<25 published records) and from southern British Columbia.
 
Authors / Contributors
Global Information Author: Cordeiro, J.
Last Updated: Aug 24, 2005
Provincial Information Author: Kristiina Ovaska
Last Updated: Apr 01, 2008
   
References and Related Literature
B.C. Ministry of Environment. Recovery Planning in BC. B.C. Minist. Environ. Victoria, BC.
British Columbia Invertebrates Recovery Team. 2008. Recovery strategy for Dromedary Jumping-slug (Hemphillia dromedarius) in British Columbia. Prepared for the B.C. Ministry of Environment, Victoria, BC. 31 pp.
Burke, T. E., M. Wainwright, and N. Duncan. 2005. Conservation assessment for four species of the genus Hemphillia. Originally issued as Management Recommendations in February 1998 by T. Burke. Revised in October 2005 by M. Wainwright and N. Duncan. USDA Forest Service Region 6 and USDI Bureau of Land Management, Oregon and Washington.
COSEWIC. 2003a. COSEWIC assessment and status report on the Dromedary Jumping-slug Hemphillia dromedarius in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vi + 20 pp.
Forsyth, R.G. 2004. Land snails of British Columbia. University of British Columbia Press. Vancouver, BC. 176pp.
NatureServe. 2007. NatureServe Explorer: An online encyclopedia of life [web application]. Version 6.2. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer (Accessed: January 08, 2008 ).
Ovaska, K. and L. Sopuck. 2003c. Surveys for terrestrial gastropod species at risk in Pacific Rim National Park Reserve. Report prepared by Biolinx Environmental Research Ltd. for Parks Canada, Coastal British Columbia Field Unit Victoria, BC.
Ovaska, K. and L. Sopuck. 2004d. Surveys for terrestrial gastropods in the Pacific Rim, Gulf Islands, and Gwaii Haanas National Park Reserves Prepared for Parks Canada. Report prepared by Biolinx Environmental Research Ltd for Parks Canada, Coastal British Columbia Field Unit, Victoria, B.C.
Ovaska, K. and L. Sopuck. 2006. Surveys of potential wildlife habitat areas for terrestrial gastropods at risk in southwest British Columbia, March 2006. Prepared for BC Ministry of Environment, Victoria, BC. 45pp.
Ovaska, K. and L. Sopuck. 2006b. Surveys for terrestrial gastropods at risk in Pacific Rim National Park Reserve, 2006. Report prepared by Biolinx Environmental Research Ltd for Parks Canada, Western and Northern Service Centre, Victoria, B.C.
Ovaska, K., L. Chichester, H. Reise, W.P. Leonard, and J. Baugh. 2002. Anatomy of the dromedary jumping-slug, Hemphillia dromedarius Branson, 1972 (Gastropoda: Stylommatophora: Arionidae), with new distributional records. The Nautilus, 116(3): 89-94.
 

Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.

Suggested Citation:

B.C. Conservation Data Centre. 2005. Species Summary: Hemphillia dromedarius. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 5, 2026).