The ladder snake (''Zamenis scalaris'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of non-venomous

snake Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more j ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Colubridae. The species is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to southwestern

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

Distribution

The geographic range of the ladder snake includes

Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of ...

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

, southern

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...

and just into

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

, also

Menorca Menorca or Minorca (from la, Insula Minor, , smaller island, later ''Minorica'') is one of the Balearic Islands located in the Mediterranean Sea belonging to Spain. Its name derives from its size, contrasting it with nearby Majorca. Its capi ...

and the Iles d'Hyères off

Provence Provence (, , , , ; oc, Provença or ''Prouvènço'' , ) is a geographical region and historical province of southeastern France, which extends from the left bank of the lower Rhône to the west to the Italian border to the east; it is bor ...

, but it is absent from northern

Iberia The Iberian Peninsula (), ** * Aragonese and Occitan: ''Peninsula Iberica'' ** ** * french: Péninsule Ibérique * mwl, Península Eibérica * eu, Iberiar penintsula also known as Iberia, is a peninsula in southwestern Europe, defi ...

including much of the

Pyrenees The Pyrenees (; es, Pirineos ; french: Pyrénées ; ca, Pirineu ; eu, Pirinioak ; oc, Pirenèus ; an, Pirineus) is a mountain range straddling the border of France and Spain. It extends nearly from its union with the Cantabrian Mountains to ...

, Galicia (although the species is found on

Ons Island The Ons Island ( gl, Illa de Ons; es, Isla de Ons) is the main island of a small archipelago in the Ria de Pontevedra in Galicia, Spain. Ons belongs administratively to the municipality of Bueu, which has a regular ferry boat connection to the is ...

, in the Atlantic Islands of Galicia National Park"''Culebra de escalera'' (''Elaphe scalaris'')"
inisterio de Agricultura, Alimentación y Medio Ambiente. Retrieved 10 April 2014. .),

Cantabria Cantabria (, also , , Cantabrian: ) is an autonomous community in northern Spain with Santander as its capital city. It is called a ''comunidad histórica'', a historic community, in its current Statute of Autonomy. It is bordered on the east ...

and the Basque Country. The population on Menorca may stem from an introduction by humans.

Habitat

The Ladder Snake enjoys scrub bushy cover, including orchards, vineyards, hedges and overgrown dry-stone walls; it is common in the maquis. Habitats with stones and boulders and low shade are preferred. Although known at altitudes over , this is a species which prefers altitudes from sea level to .

Description

The ladder snake is a medium-sized snake which reaches a maximum total length (including tail) of around but which averages . It has a pointed snout. As an adult the ladder snake is less variable than many related snake species, the basic colour goes from yellowish to dark brown, with two darker stripes running down the length of the body from neck to tail. It normally also has a dark stripe running from the rear of the eye to the angle of the jaw and sometime subtle, darker markings on the sides. The ventral side is pale, varying from a silvery-grey to whitish, with the occasional dark spot. The eye is dark. The juvenile snakes have lighter and brighter colouration, varying from yellow to light brown, with the characteristic “ladder” pattern picked out in black along the upperside. The pale underside has black markings which sometimes coalesce to cover the whole of the underside. As the snake ages these colours and patterns fade until the simpler adult pattern is left.

Food

The majority of its prey is, like other “rat snakes”, mammals such as mice, rabbits and shrews, making up 75% of prey items with a further quarter being spiders, insects (especially grasshoppers) and a few birds. To prey on birds the ladder snake will climb to search for active nests in trees or on man-made structures. Lizards are also eaten. Juveniles prefer small lizards, baby rodents, spiders, and grasshoppers.

Behaviour

The ladder snake is normally active by day, but during the hottest summer months it may be nocturnal, while in the spring months it may be more crepuscular. Its behaviour is said to be more like that of whipsnakes rather than that of

rat snake Rat snakes are members – along with kingsnakes, milk snakes, vine snakes and indigo snakes – of the subfamily Colubrinae of the family Colubridae. They are medium to large constrictors and are found throughout much of the Northern Hemi ...

s. It is more aggressive and defensive than most of the species formerly classified alongside it in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

Elaphe ''Elaphe'' is a genus of snakes in the family Colubridae. ''Elaphe'' is one of the main genera of the rat snakes, which are found in many regions of the northern hemisphere. ''Elaphe'' species are medium to large constrictors by nature. Altho ...

''. Defensive signals include hissing and lunging forward with the mouth open. Any attempt to pick up a ladder snake may be greeted by sharp bites and also the emptying of the cloacal glands, releasing an offensive odour. It is a more mobile snake than many of its relatives and movements of up to 100 m per day have been recorded, while the average home territory of an individual is 4,500 m². Adults may enter barns or similar buildings in search of rodent prey, but they do not normally use such places for shelter and prefer rodent burrows, piles of stones or hollow trees.

Breeding

In Iberia courtship occurs during May and June, however some females do not breed every year. Copulation lasts around an hour, and a clutch with an average size of 15 eggs (varies between 4 and 24 eggs) is laid 3–6 weeks after mating. Incubation takes between 5 and 12 weeks. The young measure 20 cm long as hatchlings. Unusually for snakes, their mother may remain with the newly hatched juveniles for a few days. Males and females reach sexual maturity at approximately 5 years of age, when they reach a length of 50 and 65 cm, respectively.

Conservation status

The IUCN has rated this species as Least Concern. This is a generally abundant species which is tolerant of a wide range of habitats and has a large geographic range.

Gallery

Image:ElapheScalaris-Young-199206-France.jpg, Young ''Zamenis scalaris'' in France Image:Elaphe scalaris in office.jpg, Image:ElapheScalaris-20030427-Spain.jpg, Image:Snake (Elaphe scalaris) by JM Rosier.JPG, Image:Benny Trapp Rhinechis scalaris Jugendzeichnung Portugal.jpg,

References

External links

''Rhinechis scalaris'' Information Sheet