

lizardry 6
August 2024
Tail Regrowth
A study of the speed of regrowth of the tails of two wall lizards Podarcis muralis nigriventris.
male 2.7 mm per day, Female: 1.5mm per day.
A male took 34 days to recover his original length, at an average daily increase of 2.7mm. A gravid female took 37 days to regrow after laying her clutch at an average daily increase of 1.5mm.

Regular observations have been made for four years of a population of wall lizards who have taken over a small South Devon garden ( approx 15 metres x 8 metres) , and turned the planting area, potting table, strawberry patch, patio and pots into their own secure vivarium. To assist them, leaves and garden debris were left unswept, developing hunting areas and encouraging insects.


Planting table viewed from balcony


The dry stone wall and red slab in the strawberry bed.


Patio area with moss left to spread.


Ornamental wall tiles behind which they slept coiled.
In 2021 3 males and 7 females were observed, noted and photographed on 105 days, often 3 times a day for periods from one minute to an hour, providing 4800 photographs.
In 2022 2 males and 9 females were observed on 161 days, providing 6400 photographs. Each lizard was identified by its individua face markings, and given a name, usually of Arthurian origin.

Angharad

Guinevere

Bronwen

Gladys
Guinevere and Gladys were observed in 2019, 2020, 2021 and 2022, Bronwen and Angharad in 2020, 2021 and 2022 . Six males appeared for just one year.
Observations were made either from the balcony overlooking the site, or from positions within two metres from where they basked and hunted.
This established their favourite basking rocks, hunting trails and refuges, building up a portfolio of individual behaviour. A Canon Powershot SD70 with a 30-1300 mm zoom lens provided detail.
In April 2021 a ruler placed below a favourite slab obtained accurate measurements of the lengths of several lizards, particularly helpful as Agravain and Gladys were the ones who later suffered tail loss.

Guinevere 185mm April 10 2021

Angharad 170mm May 7 2021
This meant that future pictures showing tail loss/regrowth could be shown on the PC screen, enlarged until the known body length was accurate against a ruler, thus enabling regrowth to be measured on the screen. Other parts of the site provided similar measurement factors.



The three red slabs above their favourite section of dry stone walling were 300, 100, and 200 mm. The planks on the potting table on which they basked, were 135mm wide.
In 2021 the dominant male Agravain suffered tail loss and his regrowth was recorded over a period of six weeks.

Agravain was regrowing his tail following tail loss when measured at 125mm on April 9.

Next day April 10 he attacked a new male who had come onto the table,throwing him onto the path below.




However he lost the fight with the new dominant male ( Bedivere) and was not

seen again until July 13 when he re-appeared briefly after further adventures
having lost 45mm of tail. He once again went away….

… reappearing July 23 having regrown 31mm of tail in 10 days.

Seen on July 29 having grown a total 59 mm of new tail in 16 days, an average of 3.6 mm per day.

He was seen occasionally on the potting table in the next few weeks, often in close company with Guinevere (rt) on Aug 16. His length was 168 mm, a length greater than any previously observed, and probably his original length before his two tail losses.

Gladys
Lizard Gladys was measured at 150 mm on April 9 2021

In May 2022, Gladys lost her tail when gravid, and did not begin regrowth until June 11 by which time she had laid her clutch (note her sagging back). Her regrowth was observed 26 times between May 27 and July m18. She had recovered to her original 140mm after 37 days.

Lizard Gladys was observed with a complete tail on May 24 .

She was seen on May 27 with her original length of 140mm reduced to 85mm.
She was also gravid but did not lay her clutch until June 11. This delayed her tail regrowth as her body was primarily concerned with eggs and birth. She was observed on 8 occasions between May 27 and June 11,when she was noted to have laid her clutch.


The blastema was seen swollen on June 12, and by June 20 growth was noted at 10mm. (It is interesting that the regrowths I have seen,both male and female, have had this little upward curve at the tip.)

Gladys 20.6.22

Agravain 25.7.21
In the following 19 days Gladys’ tail regrew 21mm at 1.2mm per day.

Gladys June 30
In the next eight days the tail regrew 20mm at 2.5 mm per day.

Gladys July 7
In the following 14 days the tail regrew 17mm at 1.2 per day, completing a return to her original 140mm on July 18 ( below).

Gladys was observed on 9 occasions between May 27 and June 11,when there was no regrowth.
She was observed on 18 occasions between June 11 to July 18 when she grew 55mm in 37 days at an average daily growth of 1.5mm.She was then seen 23 times between July 19 and Oct 9.

Male Agravain took 34 days to recover his length, at an erratic speed, with two periods of very fast growth. Perhaps this was caused by male testosterone?
Female Gladys took 37 days to recover her length. This was also delayed after recovering from laying her clutch which probably caused loss of energy.
Further examples would be of value, but observation in the wild would be fortuitous. These were the only two examples of regrowth seen in four years of close observation.
Raymond Wergan, Newton Ferrers, S. Devon, UK. wergan48@btinternet.com.
Visiting firemen…
italian lizards from amalfi on the adriatic….

Photos simon wergan
a grass snake inVades a sussex Picnic….

Photo annie caffyn
Burgundy is suffering from an inVasion of sPanish slugs, arion rufus……..

Photo: richard wergan
and sadly also suffering from a shortage of slug Predators!!
look out for lizard watch 7 around sePt 24th.
Raymond Wergan, Newton Ferrers, S. Devon, UK . wergan48@btinternet.com.