Identification of Poisonous and non-poisonous snakes

Identification of Poisonous and non-poisonous snakes

Near about 2500 to 3000 species of snake found all over the world. But not all the species of snake are poisonous.  Because of few of them, entire snake world have bad reputation. 
According to WHO in India about 45000  to 50000 victims die due to snake bite every year. But official record is only about  12000 to 15000. 

About 350  species of snake are poisonous. In India 216 species of snake are found and about 52 specis are poisonous . 

Many snakes are similar in appearance and colour patterns. So, there is need of clear cut identification of poisonous and non-poisonous snake. Majority of snakes are non-poisonous and harmless. The non-poisnous snakes are python, rat snake, trinket snake, freshwater snake, etc. the common poisonous snakes found in India are cobra, king cobra, Indian viper, russel’s viper, krait, coral snake, sea snake,


Identification of poisonous and non-poisonous snake is not hard task. 

Following key will serve to distinguish poisonous and non-poisonous snake.
1.    Identification of snake by the nature of bite mark
2.    Identification of snake by flow of blood from wound
3.    Identification of snake by nature of tail.
4.    Identification of snake by nature head shield or scales.

5.    Identification of snake by vertabrial

6.    Identification of snake by ventral scales.

1.    Identification of snake by the nature of bite mark:

If non-poisnous snake bites tends to several small punctures in two rows due to maxillary teeth mark and palatine teeth mark.
But if poisonous snake bite it shows two prominent spots due to fang , along with palatine teeth mark. 
 2.    Identification of snake by flow of blood from wound
When non-poisonous snake bites, blood flows from wound for short period and get clot naturally but if poisnous snake bites, blood coloured fluid continuously oozes through the wound because  venom prevent clotting of blood.

3.    Identification of snake by nature of tail.
If tail is flattened and laterally compressed then snake is sea snake and deadly poisonous. 
If we observed the tail is rounded and cylindrical, it is  land snake. Then,  snake may be poisonous or non-poisonous. 

4. Identification of snake by nature the nature of ventral scales. 

If ventral scales are broader and extending fully acros the belly. Snake may be poisonous or non-poisonous . 

 
If the ventral scales are large transverse plates extending fully across the ventral side of belly, the   snake may be poisonous or non-poisonous. Now examine the dorsal scales of the head

5.  Identification of snake by nature head shield or scales.
If dorsal side of  head is covered with shields. The snake may be poisonous or non-poisonous.

Head shield: 

If 3rd supra-labial shield touches to the nostril and eye then snake is poisonous.  The snake  may be cobra king cobra and coral snake.

 But if 3rd supra labial shield not touched to the nostril and eye then snake is non-poisonous and snake may be rat snake.

If the snakes has a small scales and large shield on the head but does not have the characters of cobra, or rat snake then examine  ventral side of head. If 4th infralabial shield extending fully from ventral side of head. Then it is poisonous snake and snake may be krait.

Scales on head 
If head is covered with smaller scale, then snake is viper and it is poisonous snake.
If head is covered with smaller scales and there is lorea pit.  it is pit viper and snake is poisonous.

 

6.  Identification of snake by nature of vertebral.
if mid-dorsal side shows presence of hexagonal scales called as vertebral the snake is  poisonous and it is krait. In addition to vertebral krait can be identified by examining 4th infra-labial shield and single row of sub-caudal.

TYPES OF BEAKS IN BIRDS - Theory and Practical

               

TYPES OF BEAKS IN BIRDS

The presence of a beak or bill is the characteristics of the bird. Beak or Bill is an elongated upper and lower jaws.  Both the beak are covered by a horny sheath called rhamphotheca.

In bird, there are various kinds of beak modifications according to food and feeding habit of birds.

The following are some common types of beak modifications in birds.

1.                 Seed eating beak                            -           Sparrow, Pigeon

2.                 Cutting beak                                  -           Crow

3.                 Fruit eating beak                            -           Parrot, Hornbill

4.                 Fish catching beak                         -           Kingfisher, Cormorant

5.                 Insect catching beak                      -           Robin, Frogmouth

6.                 Wood chiseling beak                     -           Woodpecker

7.                 Piercing and tearing beak             -           Vulture, Eagle

8.                 Flower probing                             -           Hummingbird

9.                 Mud straining beak                      -           Duck, Flamingo

10.               Mud probing beak                          -           Stilt

11.               Spatulated beak                              -           Spoonbill

12.               Pouched beak                                 -           Pelican

1.  Seed eating beak 

1. The seed-eating beaks are weak short and stout.

2. The beak is conical peg-like and pointed at the tip.

3. These type of beak are found in small seed-eating or graminivorous birds.

Ex - sparrows finches, pigeon, etc

2. Cutting and biting beak.

1.                 The cutting beak and strong and powerful.

2.                 These type of beak has sharp cutting edges.

3.                 Such type of beak is used for various purposes.

4.                 Such beak is used for cutting food, to break eggshell, cutting the flesh, etc.

Ex. Crows.

3. Fruit eating beak.

 1.                  This type of beak is found in fruit-eating (Frugivorous) bird.

2.                 The fruit-eating beaks are large, sharp, powerful and hooked

3.                 The upper beak is movable on the skull and is well adapted for tearing fruits  

            and break open hard nuts and seeds.

4.                 In parrot upper beak is curved and pointed at the tip while the lower beak is                   short and with sharp cutting edges.

5.                 Upper the beak is used to hold support and the lower beak is used to scoop out              the fruit flesh.

6.                 In hornbill beak look like large and  heavy but internally these beaks are 

           internally cellular and light in weight.

        Ex. Parrot , Hornbill

4.   Piercing and tearing beak.

 

1.                 Piercing and tearing beak is found in carnivorous birds.

2.                 These types of the beak are very strong and powerful.

3.                 Upper beak is curved and pointed at the tip.

4.                 The margins of the beak are very sharp.

5.                 This type of beak is adapted for piercing and tearing flesh.

Ex. Vultures, Hawks, Eagles, Kites, and Owls

5.   Insectivorous beak.

1.                 The beak is long and slender found in an insectivorous bird.

2.                 Beak is adopted for turning leaves and probing into the soil in search of insect 

            larvae.

3.                 In swift, flycatcher and swallow beak is small and strong with notched 

            mandible at the tip modified to capture insects during flight.

4.                 In frogmouth bird soft feathers (Rectal bristles) are present at the base of the                 beak. On another hand, frogmouth bird kept its mouth open during flying.                    These modifications are for to trap insect during flight

Ex.- Swifts,  swallows , Flycatchers, hoopoe,  etc.

6.    Fish catching beak

1.                 The fish caching beak is long, strong and sharply pointed.

2.                 In case of kingfisher the edges of beak are very sharp.

3.                 In cormorant the margins of the beak are toothed or serrated

4.                 These modifications in these birds are  to prevent the escape of captured                        slippery prey like fish and to capture  frog, tadpoles, Mollusca and other                      aquatic animals

Ex. King fisher, Cormorant.

7.     Wood chiseling beak 

 

1.        The wood chiseling beaks are long , straight, stout and chisel- like and are strongly articulated with the skull

2.        The skull bones are also thick and shock  absorbent neck muscles are also strong

3.        This type of beak is used for chiseling and drilling into  bark or wood of trees  for the prey, e.g.

            insects and their larvae and for nest construction

4.        It is commonly found in woodpeckers.

8.        Mud probing beak.
 

1.                 This type of beaks are very long, slender and slightly curved to probe the 

            mud underwater in search of larvae and aquatic worms

2.                 These are commonly found in stilts, snipes, sandpipers, jacanas, lapwing. etc.

9.        Mud and water straining beak.

 

1.                 Both the beak are flat and broad.

2.                 In duck the gap is present between both the beak which is covered with 

           membranous Lamellae which act as sieve or filter to strain out mud and water.

3.                 Duck take mouthful of debris. The mud and water strain out through marginal 

           lamella leaving the food particle into the mouth.

4.                 In flaming upper beak is long and curved while lower beak is short and straight 

           leads to gap between two beak. This gap is covered by lamella through which 

           mud is strain out.

Ex. Ducks, teals, geese and flamingo.

10.      Flower probing beak

 

1.                 This type of beak is long narrow and pointed for probing the bottom of                           flowers  to take honey.

2.                 These beak is slender and slightly curved.

3.                 The shape of flower is adopted with the shape of flower.

4.                 These  birds fly in front of flower in mid-air for sucking the honey or nectar.

Ex- Sun bird, Humming bird.

11.Pouched beak

 1.        It is found in pelecans

2.        The lower beak shows presence of large gular pouch.

3.        The gular pouch is an extension of skin and attached to the mandibles for 

           storing engulfed fish.

Ex. Pelican

12.      Spatulate beak.

1.        It is  characteristics of spoon-bill

2.        Both the beak are long and flat terminated in a broad spatulate or spoon   

           like expansion.

3.        The spatulate expansion is used for dabbing in mud below water and in 

           search of fish ,tadpoles, worms , insects and other small aquatic animals.

           

Ex. Spoonbill 

Leg Modification in birds. By. Dr. Vidhin Kamble

                     

Leg / Feet Modifications in birds 

The birds are creatures, that adopted for true aerial flight.  In birds, the forelimbs are modified into the wing and hind limbs are for bipedal movement.  In the case of birds, there are several kinds of feet/leg modifications are according to the habits and habitat which are as follows.

1.   Perching feet

2.   Raptorial feet

3.   Scratching feet

4.   Climbing feet

5.   Climbing feet

6.   Clinging feet

7.   Wading feet

8.   Swimming feet

9.   Cursorial feet.

10. Thermoregulatory feet

1.     Perching feet. sparrow, crow, pigeon      

  

These modifications are observed in the majority of birds. The toes are slender and weak. In these birds, 4 toes are present. 1^st toe directed posterior/backward and three toes directed forward. The toes are opposable. Because of this, when birds seat on the branch, their body weight falls on toes, due to this, toes turn backward automatically because of tendons attached to it. This modification helps to perch the twig or branch very firmly.

2.     Raptorial feet:- Ex. Vulture, kites, owls, eagle.

In this type of feet modification, the legs are very strong used for grasping and holding the prey.  The toes are four in number. The toes are strong and powerful with sharply pointed claws.  A lower surface of the toe is rough due to the presence of a horny spine. Such type of feet is found in carnivorous birds. These toes are modified for firm grip around captured prey during flight.

3.     Scratching feet: ex. Fowl and peafowl

In this type, the feet are long and slender.  There is the presence of four toes. 1^st toe directed backward and 2^nd, 3^rd, and 4^th toes directed forward. The toes are long and slender with sharp claws. These types of feet are modified to scratch the ground to expose food grains, grubs, and tiny food particles. In the male there is the presence of sward like a tarsal spur, used for fighting. Hence, it is also called a fighting spur.  Spur is a sexually dimorphic character in these birds.

4.     Climbing feet : Ex. Parrots, woodpecker 

The feet modifications are adapted for climbing on the vertical surface. In parrot 4 toes are present. 1^st  and 4^th toes directed backward. Whereas, 2^nd and 3^rd toes directed forward.  In woodpeckers 1^st and2nd  toes directed backward and 3^rd and 4^th toes directed forward. Such type of feet modifications is called as heteroductylous or zygoductylous feet. The toes are with sharply pointed claws. Such type of feet are used to climb on the stiff vertical surface of the tree trunk or barks.

5.     Clinging feet – Ex. Swift, swallow

In these feet, toes are slender. All the four toes are directed forward. Such type of modifications are called homoductylous feet. Such type of feet is used to cling with vertical walls and ceiling.

6.     Wadding feet:- Heron, jackana, lapwing

Walking of aquatic vegetation is called wading. In this type the legs are long and slender. The toes are free, elongated and slender adopted for walking over aquatic vegetation.

7.     Swimming feet:-  e.g. Duck, Cormorants, Coot.

Swimming type of feet is found in waterside birds, adapted for swimming and floating. In these types of feet, the membranous skin fold is stretched between the toes forming a web. The web acts as a paddle for swimming. In the case of duck, the web is present between front toes. In the case of cormorant,  all the toes are included in the toes while in the coot web is lobe like.

8.     Running or Cursorial Feet: eg. Rhea, ostrich, bustard, etc.

In running birds, the feet are strong and powerful. In these birds, the number of toes is reduced. Poster toe is greatly reduced or absent. In the case of Rhea, Emu, bustards, etc. the toes are short and only forwardly directed 3 toes are present. in the case of ostrich, only two toes are present i.e. 3rd and 4th toes. All the toes terminated with the nail plate. These feet modification is used for fast running on the open ground.

Thermoregulatory feet.

Such type of feet is found in ptarmigan in the Antarctic region. In this bird, there are only forwardly directed three toes are present.  the toes are covered with soft feathers, which at as insulators to prevent loss of heat from the body. Hence, such type of feet is called thermoregulatory feet.